This is how I feel about the Hollywood event, it definitely seems like the vast majority of people are over 21. I could be completely wrong about that, though -- as I've gotten older, I've gotten terrible at determining someone's age. Like unless they're clearly over 30, they could either be 14 or 27, I have no idea lol.
Obviously Knott's and Six Flags have their chaperone policies, but those are suburb teens -- I tend to think L.A. teens aren't quite as interested, or they have better things to do.
All the bad behavior I see is from aggro dudes in Raiders jerseys and baggy jean shorts.