Maybe I'm just old school, but if I offer to buy a woman a drink it's clear that I'm interested in getting to know her better and if she accepts, I assume there is some interest on her end. Granted, I've only done it once which led to a long-term relationship, but going into it knowing you're just using the guy for free drinks seems a little bitchy to me.
Then again, most guys probably deserve it.
I used to shoot pool for additional income on nights/weekends, but when chicks started hitting on my now ex-wife right in front of me, I laughed at first... then threesome opportunities became a discussion which she wanted no part of.
My point is that chicks handle rejection way better than most guys.