"I've been to a fair few sing a rounds and such with Pierre. Many situations where the quietest performer is usually overwhelmed by background chatter. PlC is not one of those."

Yes, Tam. I agree with your comments on PlC. I also think you're right to point out the background chatter that goes on. (For general information, Tam and I often go to the same sessions.) The odd quietly spoken or whispered comment, or even heckle, where appropriate, is neither here nor there, but it's sometimes the case that a performer will sing his or her song, preferring, if not expecting, the attention of others, and then burst into full-blown gossip mode when the next person starts singing. I don't like to be bossy, so I don't generally make an issue of it, but I am aware of it, and I think it's rather disrespectful to the performer, and I find it quite tiring trying to listen to someone play or sing while there's chatter going on. It doesn't affect me so much when I sing 'cos I've got a voice like a foghorn, but it's hard on those who sing more quietly.

The above applies primarily to the singarounds that I go to. I obviously wouldn't apply the same criteria to pub gigs. As for amplified "concert style" performances....hmmm, I'm not sure; I suppose it depends on the situation.