It's interesting that some singers deliberately shut their eyes as they believe it's traditional. Personally I prefer it when people leave their eyes open - I always do when singing. It seems a bit rude to me to shut your eyes, as if you can't stand looking at the audience.

As for the presence or absence of beards, long hair, baldness, and Guinness - yes, you do get plenty of all of these in folk clubs, but you also get plenty of people who are clean shaven, have short or medium length hair and drink other things (as for me, I prefer real ale given the choice, but I drink Guinness if there's no decent ale available, as I quite like the taste even though it's not "real" in the CAMRA sense. Sadly the "real" bottled Guinness of yesteryear is no longer available, at least in England).

Oh, and you forgot to mention the Arran sweaters ;-)

You seem to get more people wearing what might be described as "weird" clothes and funny hats, etc., at festivals, than in clubs. It seems people like to dress in "folkie" gear for these events.