Hows about a different slant on the original question.
I attend a weekly unique (in my experience) session/open mike where the singer/instrumentalist performs three songss/tunes thru P.A. Anyone else is free to play/sing along. The original idea was to encourage new/novice players to learn/practice in a friendly atmosphere with experienced musicians.
Pub visitors sit in the room & enjoy a free show which on any one night can consist of Folk, Country, Blues, Rock and Classical guitar. (One night a superb flamenco guitarist turned up and brought the house down in appreciation).
I recently walked out of a session when three other 'musicians' had a conversation across a wide table which caused them to shout to be heard. When I sang louder to compensate they commented that I sang too loud! Two of these were new arrivals in the area (excellent musicianns) whilst one is a well known local 'look-at-me-I-am-great' folk singer.
I decided that if they wouldn't show me respect, I couldn't show them any and could no longer support (i.e. play along) their 'spot'.
Punters noise we accept but shouldn't have to suffer it from within.
Whaddya think?