Wrong! Because "Unseen Attacker" rules are from 2014, and we are talking about 2024. The Invisible condition in 2024 is a replacement for "Unseen Attacker" rules.
Breaking cover doesn't mean a character is automatically seen, since backs can be turned. Miniatures on a map don't really deal with "facing" as a mechanic, and I don't think they need to. So long as one enemy on a battlefield has line of sight, you cannot effectively Hide.
The problem is that line of sight does not mean "someone can currently see you", it means "you can draw a line that does not intersect any opaque object or effect between the two creatures". Since 3/4 cover means 1/4 not covered, 3/4 cover does not block line of sight.
This is what I mean by people being hung op on outdated definitions. I'm going to ask that you use description as it appears in the 2024 DMG.
Line of Sight
To determine whether there is line of sight between two spaces, pick a corner of one space and trace an imaginary line from that corner to any part of another space. If you can trace a line that doesn’t pass through or touch an object or effect that blocks vision—such as a stone wall, a thick curtain, or a dense cloud of fog—then there is line of sight.
The rules glossary, among other things, tells us what we can do in the game, so such things must be possible. Whether you choose to accept that or not is a personal matter, but it doesn't change reality. Game mechanics may be described using Terms of Art. You can, in fact, have Three-Quarters Cover that breaks line of sight.
Having typed that, I am not saying all instances of Three-Quarters Cover will break line of sight. Heck, I'm not even saying all instances of Total Cover will break line of sight. I'm saying the Hide action gives us a checklist of two. If and only if you can check off both can you Hide.
Personally, I think a diagram would help people visualize this.
I keep seeing people say that, but I can't see it for myself. Personally, I think some of you are either too hung up on the 2014 rules or intentionally looking for absurdities because you want a game to be idiot-proof. And, to that, I say "come on." The rules for Unseen Attackers and Targets were too limiting, because they only applied during combat, whereas the 2024 rules are more broadly applicable. And pom-poms, seriously?
The rules for Unseen Attackers and Targets only apply when attacking or being attacked, which is only possible in combat, so I'm not sure what your point is. As for pom-poms, the point of examples like that is to make the absurdity more obvious. There are three basic options for how stopping hiding works in 2024
You are considered to stop hiding when you lose the prerequisites for the hide action. As written, this is completely useless as you can only hide when no-one can see you. If we toss or modify the 'no enemy has line of sight' rule so people can actually hide behind 3/4 cover" (I assume the intent is "3/4 cover, total cover, or heavy obscurement, from all enemies"), it's merely extremely marginal.
You only lose the hiding condition under the specific conditions listed in the hide, in which case, yes, pom-poms do not cause you to stop hiding.
Somewhere in between, and we have absolutely no indications of where that line is intended to be.
My guess is that RAI is (3)... but they don't say, and it's not really a usable rule without more detail.
Regardless of whatever you think the intention is, we have the rules as written plain as day.
You stop being hidden immediately after any of the following occurs: you make a sound louder than a whisper, an enemy finds you, you make an attack roll, or you cast a spell with a Verbal component.
So, unless I'm missing something, it looks like the only concern with the pom-poms is how loud they are. And if that's the case, then I think the rule already has them covered.
As many of you may already know, the Hide Action has an errata:
Hide [Action] (p. 368)
In the second paragraph, “you have the Invisible condition” is now “you have the Invisible condition while hidden”. In the third paragraph, “The condition ends on you” is now “You stop being hidden”.
It now reads:
Hide [Action]
With the Hide action, you try to conceal yourself. To do so, you must succeed on a DC 15 Dexterity (Stealth) check while you’re Heavily Obscured or behind Three-Quarters Cover or Total Cover, and you must be out of any enemy’s line of sight; if you can see a creature, you can discern whether it can see you.
On a successful check, you have the invisible condition while hidden. Make note of your check’s total, which is the DC for a creature to find you with a Wisdom (Perception) check.
You stop being hidden immediately after any of the following occurs: you make a sound louder than a whisper, an enemy finds you, you make an attack roll, or you cast a spell with a Verbal component.
So, if you are hidden, and you come out of what is making you concealed, you are no longer invisible if an enemy can see/find you. Since 5e does not have facing rules, it assumes creatures and characters always have their head an a swivel and essentially see 360 degrees. The DM could rule you stay concealed if you are still heavily obscured, your enemies are distracted, you are in a crowd that makes you essentially invisible, etc.
The rule was never intended to make you invisible as you stroll across an open square full of guards just because they could not see you hiding behind a door before you walked out. Hiding always requires a bit of common sense and DM interpretation.
The way an "enemy finds you" is described in the previous paragraph. They make a Perception check with a DC equal to your Stealth.
In terms of strolling across an open square full of guards actively looking for you, that's nearly impossible under the existing rules. Every one of those guards would get a Perception check, likely at Advantage. If even one of them succeeded, then you'd be discovered.
The way an "enemy finds you" is described in the previous paragraph. They make a Perception check with a DC equal to your Stealth.
In terms of strolling across an open square full of guards actively looking for you, that's nearly impossible under the existing rules. Every one of those guards would get a Perception check, likely at Advantage. If even one of them succeeded, then you'd be discovered.
I'd actually read that as "a way to find you", not "the way...". Also, for some reason they decided not to write "you decide to stop being hidden" as one of the condition to stop being hidden, but I think we can all agree that it should be one, which then leads to the conclusion that the rules are not exhaustive and some DM interpretation of a situation becomes not only valid, but necessary.
If you don't like that, however, I default to Plaguescarred's answer. You only roll if the outcome of a check is in question. If you walk out in plain sight while guards are looking for you, it shouldn't matter that you rolled a 27 behind the door. You are automatically found when you decide to wave your hands in front of their faces.
I think the problem is people keep trying to narrate in a I stop trying to hide into their examples. The dance in front of you examples, just stroll out in a open field while people are directly looking at it etc. But odds are its more since X rolled a 25 for stealth, X caused a distraction and dashed across the courtyard while the guards aren't looking. Or if they walk around the wall to where X is, X covered themselves with their cloak and looks like rubbish against the wall, X climbed up a bit out of their direct line of sight, the classic movie holding themselves up between rafters move, heck another momentary distraction and they repositioned to right behind the guard etc. While its a turn based game people aren't literally frozen in place, there will be some adjustments to take into account the stealth/perception checks. Yes I am sure there can be some examples where it would automatically break. But in most cases it really can just come down to narrating the rolls.
I think the problem is people keep trying to narrate in a I stop trying to hide into their examples. The dance in front of you examples, just stroll out in a open field while people are directly looking at it etc. But odds are its more since X rolled a 25 for stealth, X caused a distraction and dashed across the courtyard while the guards aren't looking. Or if they walk around the wall to where X is, X covered themselves with their cloak and looks like rubbish against the wall, X climbed up a bit out of their direct line of sight, the classic movie holding themselves up between rafters move, heck another momentary distraction and they repositioned to right behind the guard etc. While its a turn based game people aren't literally frozen in place, there will be some adjustments to take into account the stealth/perception checks. Yes I am sure there can be some examples where it would automatically break. But in most cases it really can just come down to narrating the rolls.
I, personally, don't have a problem with this as long as the conditions for remaining hidden (not becoming hidden) are narratively available. I would push back on the idea that they always are, however. I also don't have a problem with rogues getting their advantage/sneak attack as long as the attack comes immediately before/as they become found (by... making an attack roll). It is my belief that most people start this discussion with SA in mind, but then it quickly devolves into:
A: The rules say I'm invisible until these very specific conditions are met (walking out into the open not being one of them). B: That produces ridiculous bordering on insane results. A: But it's the rules. B: Not if you consider DM discretion on whether a thing is possible. A: Yeah huhh. B: Nah uhh. ...
I think the problem is people keep trying to narrate in a I stop trying to hide into their examples. The dance in front of you examples, just stroll out in a open field while people are directly looking at it etc. But odds are its more since X rolled a 25 for stealth, X caused a distraction and dashed across the courtyard while the guards aren't looking. Or if they walk around the wall to where X is, X covered themselves with their cloak and looks like rubbish against the wall, X climbed up a bit out of their direct line of sight, the classic movie holding themselves up between rafters move, heck another momentary distraction and they repositioned to right behind the guard etc. While its a turn based game people aren't literally frozen in place, there will be some adjustments to take into account the stealth/perception checks. Yes I am sure there can be some examples where it would automatically break. But in most cases it really can just come down to narrating the rolls.
Yeah. As long as there are narrative excuses available, it can work. There's only a problem when people try to impose a simple mechanical interpretation on all situations.
I think the problem is people keep trying to narrate in a I stop trying to hide into their examples.
No, the problem is that "stop trying to hide" is not in any way defined.
"stop running" is not in anyway defined. "stop fighting" is not in any way defined. "stop searching" is not in any way defined. Why do we need explicit rules for "stop trying to hide" but not for anything else?
"stop running" is not in anyway defined. "stop fighting" is not in any way defined.
You stop action when you stop spending your action to run, you stop fighting when you stop spending your action to fight. If hiding required you to take an action every turn (or even something that's not an action but still well defined), stopping hiding would be well defined, but it doesn't.
The reason why this debate won't die is because one side of it is arguing in bad faith, making up rules about line of sight that simply don't exist. It's not about a RAW reading of the rules anymore, or even RAI for that matter. It's about what DMs want for their tables. Some people here just clearly hate stealth and want an excuse to effectively ban it from their games by making it so impractical to use that nobody would want to. It's that simple.
The rules, the SAC, the errata, and various spells and items description all give more than enough evidence to understand how stealth works, both RAW and RAI. The way stealth checks work is defined, the way the "hidden" game state works is defined, and the situations in which this game state ends are also defined. The disagreements can be basically summarized as "I'm the DM in my games, I rule them however I want, so I'm gonna rule that this happens instead." And there's really no point arguing with that...
The unseen attacker rules haven't gone anywhere. See https://www.dndbeyond.com/sources/dnd/br-2024/playing-the-game#Cover (it's a box with no link).
The definition I was quoting is the dictionary definition of line of sight.
This is what I mean by people being hung op on outdated definitions. I'm going to ask that you use description as it appears in the 2024 DMG.
The rules glossary, among other things, tells us what we can do in the game, so such things must be possible. Whether you choose to accept that or not is a personal matter, but it doesn't change reality. Game mechanics may be described using Terms of Art. You can, in fact, have Three-Quarters Cover that breaks line of sight.
Having typed that, I am not saying all instances of Three-Quarters Cover will break line of sight. Heck, I'm not even saying all instances of Total Cover will break line of sight. I'm saying the Hide action gives us a checklist of two. If and only if you can check off both can you Hide.
Personally, I think a diagram would help people visualize this.
Regardless of whatever you think the intention is, we have the rules as written plain as day.
So, unless I'm missing something, it looks like the only concern with the pom-poms is how loud they are. And if that's the case, then I think the rule already has them covered.
As many of you may already know, the Hide Action has an errata:
Hide [Action] (p. 368)
In the second paragraph, “you have the Invisible condition” is now “you have the Invisible condition while hidden”. In the third paragraph, “The condition ends on you” is now “You stop being hidden”.
It now reads:
Hide [Action]
With the Hide action, you try to conceal yourself. To do so, you must succeed on a DC 15 Dexterity (Stealth) check while you’re Heavily Obscured or behind Three-Quarters Cover or Total Cover, and you must be out of any enemy’s line of sight; if you can see a creature, you can discern whether it can see you.
On a successful check, you have the invisible condition while hidden. Make note of your check’s total, which is the DC for a creature to find you with a Wisdom (Perception) check.
You stop being hidden immediately after any of the following occurs: you make a sound louder than a whisper, an enemy finds you, you make an attack roll, or you cast a spell with a Verbal component.
So, if you are hidden, and you come out of what is making you concealed, you are no longer invisible if an enemy can see/find you. Since 5e does not have facing rules, it assumes creatures and characters always have their head an a swivel and essentially see 360 degrees. The DM could rule you stay concealed if you are still heavily obscured, your enemies are distracted, you are in a crowd that makes you essentially invisible, etc.
The rule was never intended to make you invisible as you stroll across an open square full of guards just because they could not see you hiding behind a door before you walked out. Hiding always requires a bit of common sense and DM interpretation.
The way an "enemy finds you" is described in the previous paragraph. They make a Perception check with a DC equal to your Stealth.
In terms of strolling across an open square full of guards actively looking for you, that's nearly impossible under the existing rules. Every one of those guards would get a Perception check, likely at Advantage. If even one of them succeeded, then you'd be discovered.
I'd rule an enemy find hidden creature coming in plain view by automatically succeeding its Wisdom (Perception) check, no roll needed.
I'd actually read that as "a way to find you", not "the way...". Also, for some reason they decided not to write "you decide to stop being hidden" as one of the condition to stop being hidden, but I think we can all agree that it should be one, which then leads to the conclusion that the rules are not exhaustive and some DM interpretation of a situation becomes not only valid, but necessary.
If you don't like that, however, I default to Plaguescarred's answer. You only roll if the outcome of a check is in question. If you walk out in plain sight while guards are looking for you, it shouldn't matter that you rolled a 27 behind the door. You are automatically found when you decide to wave your hands in front of their faces.
Likewise, an enemy coming around a wall behind which a creature hide would automatically find it just as easily as i wouldn't ask for any roll.
I think the problem is people keep trying to narrate in a I stop trying to hide into their examples. The dance in front of you examples, just stroll out in a open field while people are directly looking at it etc. But odds are its more since X rolled a 25 for stealth, X caused a distraction and dashed across the courtyard while the guards aren't looking. Or if they walk around the wall to where X is, X covered themselves with their cloak and looks like rubbish against the wall, X climbed up a bit out of their direct line of sight, the classic movie holding themselves up between rafters move, heck another momentary distraction and they repositioned to right behind the guard etc. While its a turn based game people aren't literally frozen in place, there will be some adjustments to take into account the stealth/perception checks. Yes I am sure there can be some examples where it would automatically break. But in most cases it really can just come down to narrating the rolls.
I, personally, don't have a problem with this as long as the conditions for remaining hidden (not becoming hidden) are narratively available. I would push back on the idea that they always are, however. I also don't have a problem with rogues getting their advantage/sneak attack as long as the attack comes immediately before/as they become found (by... making an attack roll). It is my belief that most people start this discussion with SA in mind, but then it quickly devolves into:
A: The rules say I'm invisible until these very specific conditions are met (walking out into the open not being one of them).
B: That produces ridiculous bordering on insane results.
A: But it's the rules.
B: Not if you consider DM discretion on whether a thing is possible.
A: Yeah huhh.
B: Nah uhh.
...
Yeah. As long as there are narrative excuses available, it can work. There's only a problem when people try to impose a simple mechanical interpretation on all situations.
No, the problem is that "stop trying to hide" is not in any way defined.
"stop running" is not in anyway defined. "stop fighting" is not in any way defined. "stop searching" is not in any way defined. Why do we need explicit rules for "stop trying to hide" but not for anything else?
You stop action when you stop spending your action to run, you stop fighting when you stop spending your action to fight. If hiding required you to take an action every turn (or even something that's not an action but still well defined), stopping hiding would be well defined, but it doesn't.
The reason why this debate won't die is because one side of it is arguing in bad faith, making up rules about line of sight that simply don't exist.
It's not about a RAW reading of the rules anymore, or even RAI for that matter. It's about what DMs want for their tables.
Some people here just clearly hate stealth and want an excuse to effectively ban it from their games by making it so impractical to use that nobody would want to.
It's that simple.
The rules, the SAC, the errata, and various spells and items description all give more than enough evidence to understand how stealth works, both RAW and RAI.

The way stealth checks work is defined, the way the "hidden" game state works is defined, and the situations in which this game state ends are also defined.
The disagreements can be basically summarized as "I'm the DM in my games, I rule them however I want, so I'm gonna rule that this happens instead."
And there's really no point arguing with that...