I would say that asking a friend or acquaintance is acceptable. Standing outside the lounge and asking strangers is pretty clearly tacky.

Although, having been a victim of "sir, the club is at capacity, you'll have to wait for people to leave" I have wondered to myself how many people inside are actually members and how many are guests. I know inviting a guest is a stated benefit, but during high traffic times it would be nice if it were limited in some way.