I think it's a matter of mindset. We turn up, as a punter, with a checklist for having a good time, they turn up with dishonest intentions. By the time you realise you're in a shit situation it's too late.
All the through the build up, we're waiting for the bombshell, the scam, then the meeting is on. The next part is will she or won't she turn up, will she fulfill the promise, will she stay? So many questions!
Finally, you're alone together, you want her to be relaxed and to have a good time, repay the trust she has shown in you. Ultimately, it's the price of being a gullible fool! If she's alone, I'm not sure she has committed a crime, it's more of a civil case, like paying a deposit to a builder who is, subsequently, never available.
Learn from your mistakes, and the mistakes of others, make it clear from the outset that the money will be paid after the event. If they don't like it, move on. If they have some sob story, then it's equally likely to be part of a confidence trick as being genuine. Either way, it's unlikely to be a comfortable time, without trust, move on.
For the purists, my attitude is wrong but I don't care. I'm paying for a shag with an attractive semi-pro, I'm not paying for a con. They're selling, I'm buying, if their attitude is wrong then I'll look somewhere else. They are a non-essential in my life, I can live without. If there are no benefits coming my way then there are none going there way.