If someone wishes to use one of my instruments at a club or session i will of course oblige them, after all, they may have travelled some distance to attend, and by public transport carrying an instrument it's no easy deal, also they might just have accidentally just found the session etc etc.
Why alienate prospective attendees? is it some people are upset when an able player wants to share his/her talent?
Niggardly attitudes spoil occasions.
Oh yes, and if the player happens to be a fabulous singer and a wizard guitarist i warmly applaud their skill and compliment them on
having taken the time to learn to play properly, not slag them off in cyberspace like some losers here.