@Insomnia Prostitution is the world's oldest profession and honestly, sex for favors is hardly new or unusual. Good for her for getting what she wanted and being safe. I'm not a fan of demonizing or demeaning sex trade or sex workers.
There are always going to be people like that, and sure, sometimes they are obnoxious. They are also playing to an expected societal role (helplessness, less skill than men, etc). There's nothing wrong with admitting one doesn't know how to play or needs help.
That all being said, people will always play people for free stuff - be it sex related, friendliness or whatever. Some people are just good at asking for things. I imagine a lot of cons start with simply asking for a boost or handout.