I'm fine with headbanging, as long as the hair doesn't hit others or go into their drinks. Even if it's just hitting you, it is annoying and distracting to the people, behind them, trying to concentrate on the show and have fun. I know that it isn't intentional, but a quick look behind you isn't a lot to ask, before you start. And yes, I have moved, when it annoyed me and I realized that they were oblivious to what they were doing.
Moving to the seats does not necessarily protect you either. For example, at PPIV, a couple of good friends and I were
HEAVILY ANNOYED by a few guys, in the row in front of us, that were slapping us, a lot, with their sweaty hair. Cooler heads prevailed, so we moved and that was the end of it. That was incredibly fortunate for them, because my friends know Kenpo (one of them at Brown Belt level). Hopefully, a blissfully ignorant, offensive headbanger doesn't do that to anyone skilled in the martial arts or any other kind of skilled fighter without a good moral code and a sense of restraint (not to mention a desire to
NOT be kicked out of the festival
)!
I realize that this is a minor issue, when compared to moshing and smelly, drunken people trying to start fights (i.e. the guy with the Union Jack t-shirt at PPVI...I think), but people shouldn't have fun at other people's expense. I
don't think that headbanging, in general, should be banned though. Just don't be an asshole about it and don't expect people to tolerate bad behavior just because that's what you
feel like doing at the time.