It used to be super common at Booby Trap and still is at Diamond Dolls in Pompano. The reasons they were in there varied. Some of them were careful to mind their own business, others were more adventurous let's say. I've had a few hold it or shake it for me; a few not so subtly just looked, in a humerus/joking kinda way. The ones that were adventurous in there only messed with customers they knew, its not like some rando fat, ugly, mean stripper was in there peeping and creeping.
It never really bothered me in the least. It used to shock me how freaked out it made a lot of guys. I've seen many guys see a girl in there and turn around and leave. Quite a few hurriedly zip up and rush out, I'm pretty sure one day I saw a guy get his junk tangled in his zipper in his haste. Quite a few pissed on themselves and I'm pretty sure one dude literally shit his pants at the urinal. Guys used to complain to management, and it was the most hilarious thing. I remember one manager literally say "Just so I'm clear, you're complaining to me that a woman might have seen your private parts, is that what's happening right now, do you realize where you are?" Managers would periodically yell at the dancers and they'd stop going in there for a few weeks, but it never lasted. The only reason they don't do it now is cause they have their own bathroom with their own bathroom troll. That and the Cuban chicks are just much more businesslike, they don't fool around like that.