Well, the alcohol connection may be a bit of a hard sell, as I have dragons that generate alcohol through their metabolism to fuel their flight and defensive fire-breathing.
But the miscreants are a distinct possibility anyway, and they could perhaps find a way to "trade" with some juvenile dragons for some "dragon juice".
Juveniles can be a bit unpredictable anyway. They have a need for protein that isn't well satisfied by the normal vegetarian fare.
This could work, but we'll need to find a rose bush.
Thought of a disorder that may be possible in these dragons, “leaky wing” or “Effusive Wing Syndrome”, would render the so affected dragon unable to fly.
Caused by something similar to hiatal hernia, but in the dragon flight organs.