Soldier Boy, I'm glad you brought the thread back to the focus on amateur song circles and sing-arounds, where group participation is often encouraged.    I agree that the better the music sounds, the more satisfying the experience is both for participants and any "audience" that might be present.   But music - especially group singing - doesn't have to sound "professional" to be exhiliarating, moving, fun, or inspiring.    And if the song itself is a great song, that can compensate a good deal for a not-ready-for-prime-time performance.

Mary: "OK..if it doesn't sound good at all, but people are enjoying themselves...I guess that is the question. Do you want to go to this event or not? The question is not is it good for people of whatever ability to get together in a place and time of their own choosing and sing joyously together, regardless of sound produced. It is a poignant question if the event was well attended and perhaps started by great singers and now it is in great decline. "

Well, I don't know the history of all the song circles I participate in, but my experiences is that the quality of music -- and the degree of reliance on books -- varies greatly from one month to another, depending a lot on who shows up.
I have been to song circles where, no, it didn't sound very good and I, for one, didn't enjoy myself much, because of some of the things I mentioned in my last post. There's one group I lost interest in very quickly because, even WITH books in hand, people simply would not make an effort to figure out where the rests were and when to come in on the next line. But other groups can be that way one time and totally different the next. And usually there is more decent, even really good, music made than bad, so it's worth it to me. Your mileage may vary.