My players have picked up a bounty to sabotage a nobleman from competing in a jousting tournament (my fault for not having many ideas before including it on the bounty board :/ ) One of the conditions on the bounty is that it must be non-violent methods (so no murder hoboing this one!)

Does anyone have any suggestions for some challenges they have to overcome to successfully sabotage a competitor? I want it to be a bit more challenging than just roleplaying cutting the horses saddle or something like that. 

I'm thinking they're going to sabotage either the horse, the weapon or the person himself. So far my ideas are:

- The stables are secured with guards on each entrance and then each stall has an alarm spell. If they cross into the stall without deactivating the alarm spell, the guards and horse-master will descend and then detain the players. 

- The lances are kept in an armoury. They are all labelled with numbers and competitors need to draw a ballot to determine which number lance they receive. So players would need to rig the lottery somehow if they wanted to sabotage the lance

- The competitors each have their own isolated area and sleeping quarters protected by the guards. Think Olympic Athlete's Village style - only authorised personnel are allowed in. All food is controlled and tested for poison. 

If anyone has any ideas of little challenges they would need to overcome or different ways to create tension I would be so grateful! They've really hyped themselves up for a fun quest so I want to make sure it's challenging but entertaining - like Ocean's 11/Mission Impossible style.

Not Sure what king of players you are running with but i was thinking a double sabotage. setting up someone else to take the fall at the same time taking out the competitors and put them against each other and you walk away free and clear. but put in mission impossible 1 and ocean 11 together.

I was thinking if chaos were to erupt in the stables, the horses might break free and rampage throughout the room, it would go for really fun dexterity saves and challenges for the party in attempting to resolve the situation!
Perhaps one of the party members is mistaken for a participant in the jousting tournament, where said mistaken party member looks almost identical to the actual participant and confusion among the guards can arise when both characters bump into each other? If it feels off for guards or other individuals with authority to mess up participants this easily, you could always mention that they were really drunk and couldn't differentiate the differences between your player and another jousting participant.