I'd just boarded Furius Bacon at PortAventura when (shock) it went down. Then what appeared to be the entire queueline began shouting and waving their arms around in Spanish, before a fight kicked off between a group of about 10 people, most of which didn't know each other, apparently. Security turned up, they were escorted off the ride, everyone cheered and clapped, the end. According to Mrs Ride Host Woman, it was because they were queue jumping through the entire queue line, and everyone had enough. Win, I guess.
Also the Pikey events at UK parks. Ughh.