I realized that was kind of vague: last time he played he tried to keep playing after his cutoff time, and then he got escorted away from the stage by security after turning his monitors towards the crowd in an attempt to further keep playing music. I Dr. Garbanzoured he wouldn't get booked again if he was getting escorted places.
I highly doubt this would get you blacklisted from playing a festival. Pearl Jam just pulled the same shit in New Orleans a few months ago. Give the fans what they want, blah blah blah, rock and roll, blah blah.
You have to pull a Mars Volta to have that shit happen to you.