It's kind of sad when one of these types attempts to pick you up. Awkward to say the least. You try to give them a little help and they're stumbling, don't really know what to say. Eventually I decided to simply be pleasant and otherwise ignore her. There isn't much else you can do when she's coming across as only interested in you as a walking wallet.
Amusingly enough, once I'd decided "nah" and my body-language switched to "not really interested" mode she seemed to relax. She actually managed to communicate then - though I got a feeling of wistfulness from her. An odd sensation.
I wonder how the current early-twenties girls are going to act once they hit the wall. They already make me wince when they open their mouths, a mix of foulness and attitude. We'll see how things go - we live in interesting times indeed.