It's just hipsterism... just go with it and let 'em have their fun.
I'm with you Wayne... not for me. I'm thinking, "If Steve McQueen or Chuck Norris wouldn't do it, I'm not doin' it either."
Remember the neon green sunglasses phase? The ones I'm remembering were more of a thinner, wraparound style... 80's sometime. Never did that one, either. Now they're doing that, plus Atom Ant sized lenses:
I was never a hipster.