I don't think I've ever wanted to start a riot over a musical act cancelling a show, and I really love music. But that's what happened in Tulsa, Oklahoma after Travis Scott postponed a show in a very last-minute fashion... like everyone was already-lined-up-outside, last-minute.
The situation escalated when some kids started smashing venue windows in protest, trying to gain access to the building. Cops don't like that kind of behavior.