I've been in "gay nightclubs" - believe it or not it's a better place to pick up girls because they go there so as not to be hassled by stripy jumpered Stella heads who just wan't to grope and/or fight everyone.
My mate used to DJ in a few as well and I used to help him lug his gear in. I had no problem with anyone propositioning me, it only takes the word's "I'm straight" and you don't get any hassle (although they could tell I was straight because my shoes just didn't go with my outfit...

)
Some of the best, most relaxed nights out I've had are in "gay friendly" clubs/bars - because they are completely lacking in aggressive d*ckheads.