For me, it depends on whether it's a session, or a paid gig.

Our weekly session is a pretty bare knuckle affair, with no etiquette beyond common decency, and no ground rules, and it works, mostly. Anyone does anything they feel up to, and them as wants joins in. This is a bit libellous, so I hope the individuals ain't listening, but recently I have told a very good friend of mine to shut the feck up during a song he was drowning out. Our friendship cooled temporarily, but the reconciliation was swift, and he bought the bagels, so that's tacit acceptance. Result: Talk at bar, playing/singing in session.

The paid gig is a different animal, as in the small pubs I have played, the asshole is usually the biggest contributor to the landlord's cash register, and I have been told of repeat gigs lost due to the best customer being made to look a total tosser, and leaving. So I've chosen to ignore, rather than get baited into some of the brilliant quips above.

Skipjack