A few random thoughts in this rather silly thread -

What is the definition of a "folk context"?

perhaps it shouldn't be called a "folk" club

Perhaps not but there is absolutely nothing you can do about it. In analogy with the tins of soup, read the the small print, the mnufacturers name, the list of ingredients and additives. If you're still not sure, give it a try and if you don't like it try a different one next time.

An interesting anecdote from the excellent evening with Tom McConville, Claire Mann and David Newey last night (see separate thread) at the Lewes Saturday Folk Club last night, a young woman we had never seen before did a floor spot and said "I'm sorry, but I don't know any traditional songs but here's one by John Martyn." and then sang Spencer the Rover. Make of that what you will.