MaryG, I have no real disagreement with people setting up the kinds of informal song circles you describe -- except that the more rules (spoken or otherwise) you set up, the smaller the group tends to be, and most music camps don't have dozens of spaces that can accommodate song circles. So if a spontaneous song circle moves to one of the 6 cabins available and decides that they won't tolerate anyone using a book or song sheet and won't take turns or otherwise seek to accommodate the shyer persons' contributions and, oh, by the way, we're into sea chanteys, so no blues allowed, etc., there often are no other places for the other 50 people who want to jam & sing to do that.

The huge circle with lots of people getting out the books and wanting the fluorescents on so they can read the mice type and everyone taking turns so if you come in late and happen to sit to the right of the last person who sang you won't get to lead a song for at least an hour -- those aren't much fun and usually don't generate much really nice music.   But sometimes, given the space limitations of the camp, we need to find a middle ground, where some people do use song sheets and the room is brighter than candlelight and there's some sort of "turn" format that keeps two or three people from alternating the lead with just each other.

I find that most of the jams and song circles in the cabins at Singtime are like that. Not a lot of use of books or sheet music but few seem to mind if someone does. Where the turns generally go around in a circle but many people pass and/or perhaps ask if they can do a "piggyback" song out of sequence.