Jaysus! The poor singer. I've always found it quite hard to swallow when ANY musician deigns to tell ANY other musician at a session how to play or sing. It's presumptuous and pompous. If one feels that something absolutely has to be said one should pick a different time or place. I believe, had I been put in a similar situation, I would simply have stopped singing altogether and quietly gone up to the bar AND I would have resisted any attempts or urgings to offer my "services" again.
Hey everyone, they are sessions! not performances....sometimes you take the great moments with the not so great ones. If something not quite up to par takes place, it makes the up to par things seem all that much better.