Lots of things factor in here.... type of club, music, the chic....
If you're in a nice club and see a respectable-looking girl out there just kinda dancing, you probably wouldn't want to go up to her and stick a hard cock against her ass....
on the other hand, if you see a freak out there, then it's probably okay....
I think it's an on-the-fly judgment call.... different situations require different measures....