I almost totally agree with the comments passed here thereis no excuse for rudeness during a performance and it should be stepped on immediately.
However I am not sure that the silence rule can or even should be applied in a puplic bar scenario which was implied in one of the posts.
after all some of the customers may be using the pub for a social evening unaware and uninterested in any musical event that may be happening and it is of course their right to enjoy the facilities as well as us. You may not agree with me about this you all seem to have more experience than I do.
I played last night in a small bar last night The Red Lion and we had a few regulars in who were not too chuffed about it, so rather than a confrontation we changed our set a little to include some of their favourite songs and we ended up having a very good evening.

Graham (Guernsey)