Oh, FFS, shut up, already... all of you.

Wear a helmet or don't, and allow the other guy to do the same.

You're not smarter because of your choice. There's no definitive evidence to support either side, so do what you personally feel is in your own best interest (and lose this crap about paying more for the guy who chose not to, that's crap, too).

Bottom line... MYOB.