I'm not going to disagree with any of the previous comments but would make a couple of points.

Crib sheets if used dicretely and in moderation enable some people to participate more confidently knowing they have a safety net. Though I agree that one should try not to use them if possible.

Having said that, the following link indicates that some surprising people are not averse to using them. I witnessed this performance and most people in the audience wouldn't have spotted the music stand, even though it's very obvious on the video, or noticed that the words are being read as they are sung. I know it was the second gig on a tour but that's not really an excuse.

https://www.youtube.com/watch?v=amcqELOXDFc

Learning words is a problem for some people. When I was working I had lots of 'stuff' in my head which is now 'junked'. Learning songs now seems possible where it wasn't before - though it can take weeks before I can recall the lyrics confidently. And then, of course, in the singaround situation panic scrambles the brain cells.

Singarounds seem to be for the benefit of the participants and may not necessarily attract an audience at all.

I agree with Derrick's comments fully - as long as we remember that someone over 60 may well be 'starting out on a performance career' (perhaps better described in many cases as just enjoying the opportunity to have a sing in the company of others). The fact that you've owned a guitar for forty years doesn't mean that you've had any time to play it during a busy working life. As long as there is a desire to improve one would hope that people so described are tolerated/encouraged/helped in the singaround situation.

When professional guests are being paid at folk club concerts there is often a different type of audience and we owe it to the audience and the guests to be professional in running the event.

I was a frequent attendee at folk clubs in the 70's when you could see top class acts nearly every night of the week in our local area. All the clubs I remember were run well, but one of the negatives, was the 'floor spot' when someone you'd never heard of and hadn't paid to see, took up an inordinate amount of time and you just wished they'd go away. I suppose there were some pleasant (and delightful) surprises but my memory banks are scarred with these unpleasant experiences. No wonder the better concert clubs are now more selective with regard to 'floor spots' or don't have them at all. And therein lies part of the reason why many singarounds don't attract audiences.