@matthewmercer How does one go about discouraging an action from your party without spoiling the game? My level 5 party is about to accidently release a dragon on themselves and half of them are brand new players. #dmhelp #dmthings pic.twitter.com/t0AUVYHxjm
— Hawke (@Skittsue) February 4, 2019
If you feel the action is grave to the game, you can have a particularly intelligent character learn (or roll to discover) a clue to the danger. Otherwise, perhaps the dragon has bigger fish to fry than them and escapes, leading to another future story thread to pursue…
— Matthew Mercer (@matthewmercer) February 4, 2019
It’s the classic improv technique of saying “Yes, and…”, or “Yes, but…”.
Your players want to do something that will unwittingly release a dragon? You let it happen, and you figure out a way to let it happen without derailing the story.
Matt’s suggestion is great – an imprisoned dragon can’t keep its affairs in order while locked up, and it’s probably far more worried about whether another dragon has stolen their territory, or if someone has plundered their treasure hoard, or if a hated rival has been able to carry out a hated agenda unopposed, et cetera. More pressing matters might mean the dragon literally just ignores the players and leaves.
Another variation might be that the dragon has suffered during imprisonment, and is weakened, and needs to recover from captitivity somewhere safe. (Although this might embolden the players to try to slay it while it’s vulnerable, if it is weak, which might not be what you want.)
Still another variation might be that the dragon is terrified of whatever managed to imprison it in the first place, and it just wants to get the heck out of dodge as quickly as possible, and leave the players going “Wait, what? The DRAGON is freaking out? Oh crap! That can’t be good!”