My brother used to make a habit of asking girls in clubs if they would sleep with him during the first five min of a conversation, 90% said no, 10% didn't. It was crudely efficient to accomplish his goal but he did end up dating some head cases.

I was never that bold or willing to have drinks thrown in my face but letting a woman know you are attracted to her is only a problem if she has a large violent boyfriend in the general vicinity. Some will be interested and some will not but some will realize they are but hadn't really thought about it. Very few get offended if you are gentlemen about it.

Of course since I have been married for about forever it has not been an issue in long time.