90% of the time it seems to me, flirting isn't for real. If a girl is EXTEMELY obvious and up front about it, then she usually just wants to flirt or tease you. Its a self-esteem boost if you flirt back, so don't fall for the game, brush them off. This actually gives you a chance they might try and flirt with you moreso, because they really want that little boost of self-esteem now. I could see Asperger's guys as being real victims of women of low character, so watch out.
Another thing I've noticed is that some girls flirt simply to make their boyfriends jealous. There was this one girl who flirted with me in college, even after telling me she had a boyfriend. Then, later I saw her making out with another guy. Even later, I found her boyfriend was in prison. Hoo boy... So seriously, my misogynism does have a source.