regarding singing at concerts, a few rules to my thinking:
1. never EVER belt it out, even when the band is looking for some audience participation, just keep it civil. keep the belting for post midnight karaoke.
2. if you can't sing, don't. you maybe can't hear yourself, but your neighbors can. clearly, dante has a hell for tone deaf singers who think they can sing (i.e., american idol)
3. even if you can sing, be considerate of your surroundings. chances are nobody is tossing quarters at your ankles before, during or after the show.
4. if you are packed like sardines in a tuna can, know that you are guaranteed to be 3 inches from someone's ear and i promise you, they don't want to hear you anymore than you want to hear them.
5. if you are drunk, keep your mouth shut. no singing, no talking, no nasty vomit scented burps.
6. shouting is not singing. your gramma ain't in the room, so there's no need to holler like you are calling the cows home.
all right....add a few of your own so ben can claim them all.