Trading sex for adventure, tickets and housework

I'm not exactly sure about the definition of a moral compass but I was surprised to read a a college woman trading 2 weeks of sex for a guided jungle tour down in Brazil. It's an adventure she has no qualms about since in her mind all of the involved parties benefited. In trading her feminine charms for a service she wasn't alone, a recent survey of students at the University of Michigan found that 27% of men and 14% of women had offered services or items in exchange for sex.

While I found these numbers to be high I wondered where the line was drawn. When you are in college and not in a committed relationship, aren't 75% of your actions revolving around sex? Does it count if you help that cute coed with her psychology homework or treat her to a Dave Matthews Band concert and get lucky later that night? I thought most people considered that a successful date rather than a transaction of goods for "goodies"!