This is already going on with strippers, they have a little card thats on there ankle that has a QR code to scan.
I think it was called stripcoin or something,I didn't save the url with info about it.
I think cam-girls is going to be the next major Sex related bitcoin area, the cam sites take almost 50% cut of the tips.
The girls already skim tips by using paypal, but most of the time they get there account closed.
They just have to have an exchange open in the Philippians where most of the Asian cam girls are located to help them cash out.