"I've found the trad ones to be extremely welcoming. More so than the anything goes ones, certainly. The traddish singaround I mainly go to always has someone or other who insists on playing something that isn't trad, but they always get a polite smattering of applause. I also think if a folk club describes itself as 'trad' there's a bit of a clue on the tin."

But that reminds me of a curious unwritten rule about quite a few trad folk clubs: that certain singer-songwriter repertoire is allowed and positively welcomed. As if it were traditional. Richard Thompson songs, Les Barker songs, Ralph McTell songs, Jake Thackray songs etc.

...Or alternatively that other rather arcane aspect of trad folk clubs: the old spoken music-hall monologue/routine. You only tend to get that, ironically, at the more trad clubs - not the "anything goes" ones. Ironically, because were someone to go to a trad folk club and launch into a Bill Hicks or Eddie Izzard standup routine, audiences would presumably regard that as inappropriate.