Could not agree more with everything that has been said by you guys. The only way something like this would be permissible in my books is if she were going with a long-time friend who I also knew. In that case, it would be different. But some dude from the bar who is clearly trying to dart her mitt??? No fing way.
That said, you've got a golden opportunity here. You essentially know that this is prolly not someone you want to be serious with (unless there is some remarkable explanation for this type of behavior that I cannot think of) and you need to take advantage of that fact.
You need to to anything and everything that you've ever wanted (anal, on a pool table, underwater, alligator **** house, etc). Really push the envelope with things, and see what kind of crazy shit you can do. Basically, do all the things you would not want to do to someone you care about. If she gets offended, who cares, you're not serious anyway.
Once you've exhausted all possible ideas, cut her loose.