So my DM had a locked door and he didn’t think much about us well... breaking it down. So, playing a Barbarian with a great axe, I went and started chopping it and then he said a dart shot from the key hole and hit me. So I said okay, forced my shield on the keyhole, and continued chopping. Then a dart just appeared and hit me. I asked if my 18ac blocked and he said it hit without rolling. Is this sloppy work on him for not preparing the dungeon for the party properly or totally fine DM behavior?
First campaign, watched a LOT of videos, 12 sessions in or so.
Typically speaking traps don't need to roll to hit, they just hit thus armour helps little. Some can have saves to avoid them but that is the DMs call.
The thing is a shield just adds to AC, it is not considered cover or the like even though it acts like it is, so it is fairly easy to treat it just like any other armour (something a trap can bypass).
I cant really answer the question as to preparation, that totally depends on the feel of the game the DM is going for and thus will vary extensively across groups.
Most traps either have an attack roll or a save, but these are not required. But now that you know the door is trapped, you must wonder what was worth trapping it for. Fight your way through it and if the DM doesn't have anything on the other side, ask him why it was trapped.
It's OK to break rules, bend rules, stretch rules, make up your own dang rules if you're the GM.
However, it should be done to further the story and make the adventure a great one.
Agreed. The goal of everyone is to have fun playing a game. The DM should focus on everyone having fun. Sometimes that does mean breaking the rules and sometimes that does mean blocking the players. And sometimes it also means doing the opposite and making things easier for the players.
I've had similar issues occur in my campaigns. Mostly if I don't want the players going through a given door at a given time, and the party insists on battering the door down anyways, they usually find solid stone behind the door. 5E's Wall of Stone spell is wonderful. :)
Rollback Post to RevisionRollBack
Watch your back, conserve your ammo, and NEVER cut a deal with a dragon!
I've had similar issues occur in my campaigns. Mostly if I don't want the players going through a given door at a given time, and the party insists on battering the door down anyways, they usually find solid stone behind the door. 5E's Wall of Stone spell is wonderful. :)
Or switch the rooms around. They batter down the door, but instead of going where you don't want them to be, they're someplace else.
I did have one door I didn't let them knock down and they got a little frustrated. BUT they had the key for it and I didn't want to make them feel dumb by telling them they had it.
"You find a key in the shape of a dragon."
"You come across a door with a dragon symbol on it."
Rollback Post to RevisionRollBack
"Sooner or later, your Players are going to smash your railroad into a sandbox."
-Vedexent
"real life is a super high CR."
-OboeLauren
"............anybody got any potatoes? We could drop a potato in each hole an' see which ones get viciously mauled by horrible monsters?"
Agreed. The goal of everyone is to have fun playing a game. The DM should focus on everyone having fun. Sometimes that does mean breaking the rules and sometimes that does mean blocking the players. And sometimes it also means doing the opposite and making things easier for the players.
Blocking players and ignoring rules to force your players to do something else is not my definition of a fun game, for anyone. If you're doing that, then you're placing the importance of your narrative goals higher than anything, or anyone, else.
If the players go somewhere you didn't intend them to go or don't want them to go, that's where imagination has to render the territory ahead of them in real time, instead of drawing from stored memory.
Rollback Post to RevisionRollBack
"Most people are other people. Their thoughts are someone else's opinions, their lives a mimicry, their passions a quotation."
Agreed. The goal of everyone is to have fun playing a game. The DM should focus on everyone having fun. Sometimes that does mean breaking the rules and sometimes that does mean blocking the players. And sometimes it also means doing the opposite and making things easier for the players.
Blocking players and ignoring rules to force your players to do something else is not my definition of a fun game, for anyone. If you're doing that, then you're placing the importance of your narrative goals higher than anything, or anyone, else.
If the players go somewhere you didn't intend them to go or don't want them to go, that's where imagination has to render the territory ahead of them in real time, instead of drawing from stored memory.
White Plume Mountain blocks the players and breaks the rules in several places and it’s a published module. The rules are broken to give the players puzzles to solve.
Many players, including me, have played enough that we know too much. Breaking the rules by changing modules, changing monsters, etc. “blocks” us but also gives us our sense of discovery back and challenges us.
The DM should never break the rules or block players.
Never is a strong word. The DM can occasionally break the rules when it increases fun, improves the story, or the written rules would result in a nonsensical situation. A great example is how before the November errata the rules would let paralyzed or stunned creatures resist a grapple attempt.
The important thing is to not undermine the players or change the base rules so much the players can't trust them. Arbitrarily punishing players for doing perfectly sensible things like blocking a dart trap with a shield isn't fun. D&D is a co-op game and that applies to the DM too.
My philosophy is that rules should be followed unless it grossly interferes with fun, is arbitrary, or violates common sense. I also sometimes believe that the rules can be bent if a player can make a compelling case for whatever action they are trying to achieve.
For instance, I remember watching an old critical role episode where a water elemental controlled by a player caught on fire. The rules said that this elemental was now aflame, but given the context of the situation, it was absurd that this being of pure water could be on fire. Consequently, the DM overruled the rules and said the elemental was not on fire. That's fine, it helps immersion, and keeps things sensical and fun.
Regarding your scenario, the DM was within his rights to have the door trapped. Even if he didn't plan for it ahead of time, sometimes it is appropriate to add an obstacle when the players exploit a loophole in your plans so as to keep things interesting. A blow gun in the keyhole is a relatively believable trap.
However, I don't think it was appropriate to then have you hit again after you came up with a clever solution to this new problem. A dart out of nowhere appears to just be an attempt at railroading you away from getting through a door he doesn't want opened yet. He is within his rights as a DM to do it, but to me that interferes with the fun, rather than creating a new obstacle to be overcome, you are being punished for your cleverness.
Of course, every group has it's own norms. Some like to keep strictly to the rules, with no wiggle room, and that works for them because that is how they like they like to play. Others like to play fast and loose, so as to tell a fun story or do crazy antics. There is really no right way to play, the most important thing is that you talk with your DM and other players so that you all know what kind of game you expect, and can adjust accordingly.
I'd be less inclined to break rules, but certainly bending them to the situation would be alright. And as long as the DM is consistent. Example...I play my potions of healing provide max health benefit, versus rolling. If I were to then change and say that they have to roll for the healing, I had better have a great rationale to justify it.
In this scenario by the OP, if I were the DM, after the dart sprung, I'd have also had the barbarian make a con save on paralysis or something. The second dart out of nowhere would be frustrating to me as a player, after blocking the keyhole. A better way would have been for the DM to say the dart originated from a pinhole overhead. Alternatively, once he began chopping at the door, I would have narrated, "Your axe barely cuts into the incredibly dense wood. You get the sense that this door has been master crafted, is incredibly strong and may take quite some time to hack it down." Then if the player insisted on continuing, I'd consider applying a level of exhaustion, depending on why I wouldn't want the group in there yet.
The idea to me is that they are welcome to continue to pursue what's behind the door, but as the DM, I'm going to discourage them to an extent. It might be a bit railroad-like, but sometimes, that's just how adventures should/need to play out. I once had 2 rogues try to pick a locked door that I didn't quite want them to open yet. I set the DC as 20 - beatable, but difficult to achieve, and even though they rolled well, they failed the challenge. My narration was simple, "you realize that this lock is beyond your current skills," and the party moved on to find the key. It was exactly what I wanted to happen as the DM, but had they succeeded, then the encounter would've ensued as I had planned.
I think that the DM can bend, or flex the rules, to further a good story.
However - there is a difference between protecting a good story, and the story the DM has in their head. The adventure setup, basic conflict, NPCs, and rule adjudication belong to the DM. The story events belong to the Players. If the Players find a way through story events that the DM never pictured, welcome to D&D - that's the norm :p
If the Players are about to embark on a course of action that breaks the whole adventure, the DM can either roll with it ( and sometimes that's the most interesting ), or they can suddenly switch "reality" around in the background to prevent the breakage. However, Thou Shalt Not Get Caught is the cardinal rule here, and it looks like one that the OP's DM broke. The Players should never be able to tell the DM is changing things around.
The DM should also note why the Players were able to break the whole adventure ( not the adventure in the DMs head, but the whole adventure structure ), and keep that in mind as a lesson for the next time they're building an adventure; avoid that flaw moving forward.
I'll occasionally fudge die rolls to help mitigate design mistakes I make ( maybe I shouldn't have sent that Iron Golem against that 1st level party ... ) - but not to "correct" actions the Players make.
Disclaimer: This signature is a badge of membership in the Forum Loudmouth Club. We are all friends. We are not attacking each other. We are engaging in spirited, friendly debate with one another. We may get snarky, but these are not attacks. Thank you for not reporting us.
I'd be less inclined to break rules, but certainly bending them to the situation would be alright. And as long as the DM is consistent.
Good question.
As you see from the responses each DM does things a bit differently. I'm with Fang on this, and rarely outright break a rule, though I may bend things. Once I do that however, one has to maintain consistency. As a DM I setup the world and manage it, I may create the beats of a narrative and story idea, but ultimately, it's the players and their characters actions that provide the details and the moments. I want to encourage more interesting moments that make for a good story, not discourage them.
A lot of this will depend on the DM's experience and style as well. Some are more comfortable ad libbing while others need things closer to a script.
Here's something that came up in my game last session. Hopefully it helps with design ideas as well (not that I am an expert).
The situation:
The party is in the early part of a tomb. They have met a talking skull (which drains life from them each time they talk to it), that said it can help them. They are standing before a wall, which has a rune of some sort on it that they can't recognize. They feel strongly that this is a door of some kind.
The backstory:
This is the tomb of a barbarian chief. The skull is from an ancestor shaman who found the tomb, but was then killed by a being seeking to desecrate the tomb.
As a DM: I expected the party to talk to the skull, get more information and then learn the skull could open the sealed rune-door by placing it against it and invoking her ancestry.
What the party did. At first they tried to see if they could circumvent it by digging/poking/hitting it. They didn't talk to the skull after the initial conversation. One of the party members (a fighter) leaned up against the door and said something similar to "your ancestor asks you to open this". (There was a statue of the barbarian chief earlier in the tomb). Well that was unexpected. The character was from that general area, so I had him roll to see if he was a descendant.. boom 20. The door opens.
Probably the #1 rule of running a game is that your party will always do something unexpected, so as a DM you should understand the story and situation so you can then give them freedom to solve a problem a lot of different ways (many of which you may not be able to think of beforehand).
Rollback Post to RevisionRollBack
"An' things ha' come to a pretty pass, ye ken, if people are going to leave stuff like that aroound where innocent people could accidentally smash the door doon and lever the bars aside and take the big chain off'f the cupboard and pick the lock and drink it!"
I think it also is going to depend on your party makeup. I DM for my brother and his kids. I want the kids to have fun so I've bent rules (or we've all together pretended they don't exist such as movement speed in combat) in favor of everyone having fun. The kids both play rangers, one is a beastmaster. His companion nearly got killed but thanks to the kid's imagination his companion isn't of the material plane so I was able to bend the rules and make up on the fly that his companion just returned to the water elemental plane. He got the companion back later. Per the rules, that companion should have died. But the rules were already bent by him having that companion so as DM I just rolled with it and bent the rules. He had to wait a couple weeks for his companion to return to him but the game remained enjoyable because I didn't kill his companion outright. I've also fudged dice rolls and HP remaining on enemies when I could see the fight dragging on too long (even though the kids enjoy being murder hobos in game) in favor of the game remaining fun for everyone. As DM I have to constantly read the table to make sure everyone in the group is still having fun. If rule monkeying is making it less fun, then it's my job to decide when and how to bend or break the rules to keep the party enjoying it. Because if they're not enjoying the game, they're not going to want to keep playing. If they stop playing, all the hard work I've put in is gone to waste.
As a DM, no matter how well I'm prepared, it's my creativity vs the creativity of 6 players. Now, I'm a reasonably creative fellow, but they're going to out think me every now and then. It's inevitable. And when they do, I want to reward that creativity by rolling with it and making it fun for them, not blocking it.
One example was when they were trying to kill a Red Wizard of Thay. Rather than go where he was obviously waiting for them, they charmed a low level scumbag, polymorphed into a (now dead) apprentice, and the rest of the party used rope trick to hide and then ambush him. I hadn't thought of any of this, but I thought it was a pretty good plan, so went with it. It worked really well until the Red Wizard asked about someone by name and the fake apprentice got their gender wrong. At which point the Wizard knew things were sideways and got out of there with only a little damage. It was great.
Long story short, no railroading. To me, that's the beauty of D&D. You can do ANYTHING. It's not meant to be linear.
I think the first rule of DMing, for me at least, is that you are the master of the rules. You use them to bring your narrative to life, and bring a certain order and logic to an otherwise completely fantastical world. They're the laws of the universe, but the DM is omnipotent.
Ultimately, as a DM, I use the rules to create the illusion that I'm as bound by the constraints of the D&D System as the players are. Because that's satisfying to the players, who feel they are overcoming situations through their decisions and creativity. But, at my discretion (which isn't all the time), I can change outcomes to be whatever I want them to be to provide drama, tension, or just plain old fun. Whether that's suddenly adding an additional enemy to make a final encounter more intense, increasing an enemies hit points to add challenge, or allowing a player to succeed a check they should probably have failed, because it was a creative idea and you want to reward their thinking.
But as others have touched on, creating that illusion and ensuring it is believable is paramount. In the OP's example, the illusion was broken, because the laws of the world were clearly being changed because it was obvious the DM didn't want them getting through that door without the key. This ability to react to players creativity without derailing your own narrative, is something that comes with practice.
The DM will also learn that if they only wanted that door opened by a key, then there are more satisfying ways of conveying that to players. Whether the door is made of a material unbreakable by conventional tools. Or a magical barrier. Or simply touching the door repels the players who aren't holding the key.
Unfortunately, a simple dart trap is a hinderance that can easily be overcome. The player put a shield in the way of the key hole. When this simple solution simply didn't work – with no real explanation beyond 'because I say so' – then the illusion is broken, and the player feels railroaded.
The player's creative solution should be rewarded in some way – even if they still can't get through the door. Perhaps that trap only held 5 darts, and the player has managed to take care of the trap for when they do find the key?
Ultimately, to answer tacoboy's question, the DM isn't bound by the rules in the same way the players are – but the players should always feel satisfied by the conclusion, even if it's failure. The fact your logical solution didn't work 'just because', is a failure on the DMs part to use the rules to provide a satisfactory outcome. The DM is capable of not allowing players to get through a door without a key – but the way they communicate that, and reward the players' creativity in trying to – is important.
So my DM had a locked door and he didn’t think much about us well... breaking it down. So, playing a Barbarian with a great axe, I went and started chopping it and then he said a dart shot from the key hole and hit me. So I said okay, forced my shield on the keyhole, and continued chopping. Then a dart just appeared and hit me. I asked if my 18ac blocked and he said it hit without rolling. Is this sloppy work on him for not preparing the dungeon for the party properly or totally fine DM behavior?
First campaign, watched a LOT of videos, 12 sessions in or so.
Typically speaking traps don't need to roll to hit, they just hit thus armour helps little. Some can have saves to avoid them but that is the DMs call.
The thing is a shield just adds to AC, it is not considered cover or the like even though it acts like it is, so it is fairly easy to treat it just like any other armour (something a trap can bypass).
I cant really answer the question as to preparation, that totally depends on the feel of the game the DM is going for and thus will vary extensively across groups.
- Loswaith
Most traps either have an attack roll or a save, but these are not required. But now that you know the door is trapped, you must wonder what was worth trapping it for. Fight your way through it and if the DM doesn't have anything on the other side, ask him why it was trapped.
The DM should never break the rules or block players.
What? Aside from literally only a couple of exceptions, all traps have an attack roll or saving throw.
"Most people are other people. Their thoughts are someone else's opinions, their lives a mimicry, their passions a quotation."
― Oscar Wilde.
It's OK to break rules, bend rules, stretch rules, make up your own dang rules if you're the GM.
However, it should be done to further the story and make the adventure a great one.
"Sooner or later, your Players are going to smash your railroad into a sandbox."
-Vedexent
"real life is a super high CR."
-OboeLauren
"............anybody got any potatoes? We could drop a potato in each hole an' see which ones get viciously mauled by horrible monsters?"
-Ilyara Thundertale
Agreed. The goal of everyone is to have fun playing a game. The DM should focus on everyone having fun. Sometimes that does mean breaking the rules and sometimes that does mean blocking the players. And sometimes it also means doing the opposite and making things easier for the players.
Professional computer geek
I've had similar issues occur in my campaigns. Mostly if I don't want the players going through a given door at a given time, and the party insists on battering the door down anyways, they usually find solid stone behind the door. 5E's Wall of Stone spell is wonderful. :)
Watch your back, conserve your ammo,
and NEVER cut a deal with a dragon!
Or switch the rooms around. They batter down the door, but instead of going where you don't want them to be, they're someplace else.
I did have one door I didn't let them knock down and they got a little frustrated. BUT they had the key for it and I didn't want to make them feel dumb by telling them they had it.
"You find a key in the shape of a dragon."
"You come across a door with a dragon symbol on it."
"Sooner or later, your Players are going to smash your railroad into a sandbox."
-Vedexent
"real life is a super high CR."
-OboeLauren
"............anybody got any potatoes? We could drop a potato in each hole an' see which ones get viciously mauled by horrible monsters?"
-Ilyara Thundertale
When will all these pesky dungeon designers learn to use metal doors if they don't want people chopping them down?
I tried a metal door once, but the pesky wizard polymorphed a fellow party member into a rust monster . . .
Watch your back, conserve your ammo,
and NEVER cut a deal with a dragon!
Blocking players and ignoring rules to force your players to do something else is not my definition of a fun game, for anyone. If you're doing that, then you're placing the importance of your narrative goals higher than anything, or anyone, else.
If the players go somewhere you didn't intend them to go or don't want them to go, that's where imagination has to render the territory ahead of them in real time, instead of drawing from stored memory.
"Most people are other people. Their thoughts are someone else's opinions, their lives a mimicry, their passions a quotation."
― Oscar Wilde.
White Plume Mountain blocks the players and breaks the rules in several places and it’s a published module. The rules are broken to give the players puzzles to solve.
Many players, including me, have played enough that we know too much. Breaking the rules by changing modules, changing monsters, etc. “blocks” us but also gives us our sense of discovery back and challenges us.
Professional computer geek
Never is a strong word. The DM can occasionally break the rules when it increases fun, improves the story, or the written rules would result in a nonsensical situation. A great example is how before the November errata the rules would let paralyzed or stunned creatures resist a grapple attempt.
The important thing is to not undermine the players or change the base rules so much the players can't trust them. Arbitrarily punishing players for doing perfectly sensible things like blocking a dart trap with a shield isn't fun. D&D is a co-op game and that applies to the DM too.
The Forum Infestation (TM)
My philosophy is that rules should be followed unless it grossly interferes with fun, is arbitrary, or violates common sense. I also sometimes believe that the rules can be bent if a player can make a compelling case for whatever action they are trying to achieve.
For instance, I remember watching an old critical role episode where a water elemental controlled by a player caught on fire. The rules said that this elemental was now aflame, but given the context of the situation, it was absurd that this being of pure water could be on fire. Consequently, the DM overruled the rules and said the elemental was not on fire. That's fine, it helps immersion, and keeps things sensical and fun.
Regarding your scenario, the DM was within his rights to have the door trapped. Even if he didn't plan for it ahead of time, sometimes it is appropriate to add an obstacle when the players exploit a loophole in your plans so as to keep things interesting. A blow gun in the keyhole is a relatively believable trap.
However, I don't think it was appropriate to then have you hit again after you came up with a clever solution to this new problem. A dart out of nowhere appears to just be an attempt at railroading you away from getting through a door he doesn't want opened yet. He is within his rights as a DM to do it, but to me that interferes with the fun, rather than creating a new obstacle to be overcome, you are being punished for your cleverness.
Of course, every group has it's own norms. Some like to keep strictly to the rules, with no wiggle room, and that works for them because that is how they like they like to play. Others like to play fast and loose, so as to tell a fun story or do crazy antics. There is really no right way to play, the most important thing is that you talk with your DM and other players so that you all know what kind of game you expect, and can adjust accordingly.
I'd be less inclined to break rules, but certainly bending them to the situation would be alright. And as long as the DM is consistent. Example...I play my potions of healing provide max health benefit, versus rolling. If I were to then change and say that they have to roll for the healing, I had better have a great rationale to justify it.
In this scenario by the OP, if I were the DM, after the dart sprung, I'd have also had the barbarian make a con save on paralysis or something. The second dart out of nowhere would be frustrating to me as a player, after blocking the keyhole. A better way would have been for the DM to say the dart originated from a pinhole overhead. Alternatively, once he began chopping at the door, I would have narrated, "Your axe barely cuts into the incredibly dense wood. You get the sense that this door has been master crafted, is incredibly strong and may take quite some time to hack it down." Then if the player insisted on continuing, I'd consider applying a level of exhaustion, depending on why I wouldn't want the group in there yet.
The idea to me is that they are welcome to continue to pursue what's behind the door, but as the DM, I'm going to discourage them to an extent. It might be a bit railroad-like, but sometimes, that's just how adventures should/need to play out. I once had 2 rogues try to pick a locked door that I didn't quite want them to open yet. I set the DC as 20 - beatable, but difficult to achieve, and even though they rolled well, they failed the challenge. My narration was simple, "you realize that this lock is beyond your current skills," and the party moved on to find the key. It was exactly what I wanted to happen as the DM, but had they succeeded, then the encounter would've ensued as I had planned.
I think that the DM can bend, or flex the rules, to further a good story.
However - there is a difference between protecting a good story, and the story the DM has in their head. The adventure setup, basic conflict, NPCs, and rule adjudication belong to the DM. The story events belong to the Players. If the Players find a way through story events that the DM never pictured, welcome to D&D - that's the norm :p
If the Players are about to embark on a course of action that breaks the whole adventure, the DM can either roll with it ( and sometimes that's the most interesting ), or they can suddenly switch "reality" around in the background to prevent the breakage. However, Thou Shalt Not Get Caught is the cardinal rule here, and it looks like one that the OP's DM broke. The Players should never be able to tell the DM is changing things around.
The DM should also note why the Players were able to break the whole adventure ( not the adventure in the DMs head, but the whole adventure structure ), and keep that in mind as a lesson for the next time they're building an adventure; avoid that flaw moving forward.
I'll occasionally fudge die rolls to help mitigate design mistakes I make ( maybe I shouldn't have sent that Iron Golem against that 1st level party ... ) - but not to "correct" actions the Players make.
My DM Philosophy, as summed up by other people: https://drive.google.com/file/d/1rN5w4-azTq3Kbn0Yvk9nfqQhwQ1R5by1/view
Disclaimer: This signature is a badge of membership in the Forum Loudmouth Club. We are all friends. We are not attacking each other. We are engaging in spirited, friendly debate with one another. We may get snarky, but these are not attacks. Thank you for not reporting us.
Good question.
As you see from the responses each DM does things a bit differently. I'm with Fang on this, and rarely outright break a rule, though I may bend things. Once I do that however, one has to maintain consistency. As a DM I setup the world and manage it, I may create the beats of a narrative and story idea, but ultimately, it's the players and their characters actions that provide the details and the moments. I want to encourage more interesting moments that make for a good story, not discourage them.
A lot of this will depend on the DM's experience and style as well. Some are more comfortable ad libbing while others need things closer to a script.
Here's something that came up in my game last session. Hopefully it helps with design ideas as well (not that I am an expert).
The situation:
The party is in the early part of a tomb. They have met a talking skull (which drains life from them each time they talk to it), that said it can help them. They are standing before a wall, which has a rune of some sort on it that they can't recognize. They feel strongly that this is a door of some kind.
The backstory:
This is the tomb of a barbarian chief. The skull is from an ancestor shaman who found the tomb, but was then killed by a being seeking to desecrate the tomb.
As a DM: I expected the party to talk to the skull, get more information and then learn the skull could open the sealed rune-door by placing it against it and invoking her ancestry.
What the party did. At first they tried to see if they could circumvent it by digging/poking/hitting it. They didn't talk to the skull after the initial conversation. One of the party members (a fighter) leaned up against the door and said something similar to "your ancestor asks you to open this". (There was a statue of the barbarian chief earlier in the tomb). Well that was unexpected. The character was from that general area, so I had him roll to see if he was a descendant.. boom 20. The door opens.
Probably the #1 rule of running a game is that your party will always do something unexpected, so as a DM you should understand the story and situation so you can then give them freedom to solve a problem a lot of different ways (many of which you may not be able to think of beforehand).
"An' things ha' come to a pretty pass, ye ken, if people are going to leave stuff like that aroound where innocent people could accidentally smash the door doon and lever the bars aside and take the big chain off'f the cupboard and pick the lock and drink it!"
I think it also is going to depend on your party makeup. I DM for my brother and his kids. I want the kids to have fun so I've bent rules (or we've all together pretended they don't exist such as movement speed in combat) in favor of everyone having fun. The kids both play rangers, one is a beastmaster. His companion nearly got killed but thanks to the kid's imagination his companion isn't of the material plane so I was able to bend the rules and make up on the fly that his companion just returned to the water elemental plane. He got the companion back later. Per the rules, that companion should have died. But the rules were already bent by him having that companion so as DM I just rolled with it and bent the rules. He had to wait a couple weeks for his companion to return to him but the game remained enjoyable because I didn't kill his companion outright. I've also fudged dice rolls and HP remaining on enemies when I could see the fight dragging on too long (even though the kids enjoy being murder hobos in game) in favor of the game remaining fun for everyone. As DM I have to constantly read the table to make sure everyone in the group is still having fun. If rule monkeying is making it less fun, then it's my job to decide when and how to bend or break the rules to keep the party enjoying it. Because if they're not enjoying the game, they're not going to want to keep playing. If they stop playing, all the hard work I've put in is gone to waste.
My Homebrew Backgrounds | Feats | Magic Items | Monsters | Races | Subclasses
As a DM, no matter how well I'm prepared, it's my creativity vs the creativity of 6 players. Now, I'm a reasonably creative fellow, but they're going to out think me every now and then. It's inevitable. And when they do, I want to reward that creativity by rolling with it and making it fun for them, not blocking it.
One example was when they were trying to kill a Red Wizard of Thay. Rather than go where he was obviously waiting for them, they charmed a low level scumbag, polymorphed into a (now dead) apprentice, and the rest of the party used rope trick to hide and then ambush him. I hadn't thought of any of this, but I thought it was a pretty good plan, so went with it. It worked really well until the Red Wizard asked about someone by name and the fake apprentice got their gender wrong. At which point the Wizard knew things were sideways and got out of there with only a little damage. It was great.
Long story short, no railroading. To me, that's the beauty of D&D. You can do ANYTHING. It's not meant to be linear.
I think the first rule of DMing, for me at least, is that you are the master of the rules. You use them to bring your narrative to life, and bring a certain order and logic to an otherwise completely fantastical world. They're the laws of the universe, but the DM is omnipotent.
Ultimately, as a DM, I use the rules to create the illusion that I'm as bound by the constraints of the D&D System as the players are. Because that's satisfying to the players, who feel they are overcoming situations through their decisions and creativity. But, at my discretion (which isn't all the time), I can change outcomes to be whatever I want them to be to provide drama, tension, or just plain old fun. Whether that's suddenly adding an additional enemy to make a final encounter more intense, increasing an enemies hit points to add challenge, or allowing a player to succeed a check they should probably have failed, because it was a creative idea and you want to reward their thinking.
But as others have touched on, creating that illusion and ensuring it is believable is paramount. In the OP's example, the illusion was broken, because the laws of the world were clearly being changed because it was obvious the DM didn't want them getting through that door without the key. This ability to react to players creativity without derailing your own narrative, is something that comes with practice.
The DM will also learn that if they only wanted that door opened by a key, then there are more satisfying ways of conveying that to players. Whether the door is made of a material unbreakable by conventional tools. Or a magical barrier. Or simply touching the door repels the players who aren't holding the key.
Unfortunately, a simple dart trap is a hinderance that can easily be overcome. The player put a shield in the way of the key hole. When this simple solution simply didn't work – with no real explanation beyond 'because I say so' – then the illusion is broken, and the player feels railroaded.
The player's creative solution should be rewarded in some way – even if they still can't get through the door. Perhaps that trap only held 5 darts, and the player has managed to take care of the trap for when they do find the key?
Ultimately, to answer tacoboy's question, the DM isn't bound by the rules in the same way the players are – but the players should always feel satisfied by the conclusion, even if it's failure. The fact your logical solution didn't work 'just because', is a failure on the DMs part to use the rules to provide a satisfactory outcome. The DM is capable of not allowing players to get through a door without a key – but the way they communicate that, and reward the players' creativity in trying to – is important.