I have watched at clubs, and I have been watched at clubs. I think if you want to watch some, that is fine, but it is not acceptable to go to these clubs just to watch. That is not why sincere couples go to this club. If they want to just watch, they could just buy a porn.
I feel if you are not there to participate or trying to met other couples, you don't need to be there. It can be a spectator sport sometimes, but every once in awhile you do have to throw in your ball. I can understand about being shy, but if your intentions are not to participate, you shouldn't take advantage of others'.