Sun protection panties

It makes no sense. I bought a few more pairs of the old standby, the boy-cut panties from MEC. The labels caught my eye before I ripped them off: SPF 15 sun protection. Say what?? I mean, no, of course I don't want to sunburn my ass, but why does my underwear have sun protection?



UPDATE: I ordered the thongs from the website and they too have sun protection. Hmm.