farouche - by analogy think of "wild flower"

artless: meanings 2b and 3

I think that singers and players should be wary of telling others to not to join in. It fills me at least with the desire to say "EEwww, get you!" unless there is a good reason.

I think, John, that the default position lies somewhere else. If the event is a paid for seated concert then I can see (even if I am hesitant about accepting) the "Don't join in" argument. It gets steadily more self important as one moves from that environment, unless there is a good and apparent reason.

But of course, manners should dictate "listen" as well.