Well said sir! And if you don't like what you find, then leave it and start something you do like.

I would add to that that the concept of 'proper session etiquette' is not helpful. It tends to be not much more than a personal prejudice and it builds in a sort of permission to be rude, when one sees someone else doing what 'proper session etiquette' says that they should not.

Common sense and mutual respect will cover it all perfectly well and it matters little if what is going on has been going on from the year dot, or is a new concept. Whatever is happening in public and for the public, is a fragile thing and a heavy approach places the whole concept in danger.

Let us play and let play!

Or let us sing and let sing!

Or let us play and sing and let play and sing!

Or............