I'm going to jump in here, right after friend Don, with a comment. I agree with others that the audience, in public concert, should NOT join in on the singing unless the performers invite them to do so. Performers put hours and hours of practice and planning into their performances. Sometimes songs change over the years ... new aspects arrive ... and audiences' chorus singing can spoil that.

Leave it to the performers to entertain you ... NOT the other way around. CHEERS, Bob(deckman)Nelson