I made a point of going to him directly after the show, told him how much his music means to me and what a great show it was. Got him to sign my The Inside Room vinyl as well
The guy on Iced Earth concert was pushing people so he could go closer to stage. Violently. At one point he pushed a pregnant woman. Her boyfriend/husband was this big-viking dude. He just landed his punch on the guy's nose.
Then again, respect goes both ways, doesn't it? Years and years ago I saw Finntroll and their bass player barely did the last couple of songs sitting down as he was so drunk. Ruined the whole feeling.
Years back Le Butcherettes were opening for Incubus and some dude kept yelling show me your tits, so after the third time someone punched him and knocked him and a bunch of punks started kicking him and security cleared the pit