exept Man vs Wild isn't a reality show (per se). Reality shows like The Alaska Experiment focus on interersonal drama, and the setting is irrelevant apart from the (slightly)varying levels of drama it creates. They never claim that what you see on the screen is what you should do in that situation.
Man vs Wild is touted as a serious educational endeavor, and Grylls is passing HIS stupid stuff off as legitimate survival techniques, and therein lies the difference.

as for signing up: i'd LOVE to spend a few months in Alaska, but i won't even bother with this. i'm short, chunky, hairy, well-muscled, and know how to get along outdoors. In other words, perfectly suited for actually living in a cold climate, and therefore exactly the OPPOSITE of what they're looking for. Like BOBS said, sticking people in a harsh climate who are well suited for that climate doesn't make for very entertaining television.