Another question is: What does a would-be performer sensibly do before going to a club and asking to perform? A simple guide might be:

(a) visit the club first to gauge the style and standard of the floor singers

(b) have a word with the organiser(s) to see if a floor spot on a future date is OK - and check whether that might entail learning 1, 2, 3 songs, etc.

(c) go away and practice the material they intend to perform at their 'debut' and make sure they have it ready to the best of their ability

(d) go and do the spot - and learn from any reaction, comment, advice, etc. that follows it

Sounds obvious, doesn't it? I've been playing for a long time but I would still visit, do an email or make a phone call, if possible, to a club before performing there for the first time - just to check on the protocol.