First off, I wear a helmet when I ski.
Second, its not a pro's responsibility to do anything. They get paid to ski and do what they want, more power to them, but they dont have to be responsible for people imitating them. If they did, there would certainly be a fuckload of lawsuits from people landing on their neck off JOSS size jumps.
Morally, however, if I was in the limelight, I'd probably still wear mine, reguardless of what Skullcandy or Rimeknits wanted to give me (no offense to either, they make awesome products that I am a complete fan of). I'd do it because if I'm trying a cork 7 over a road gap, it kinda makes sense to at least protect my noggin. Theres good stuff in my brain, and I rather like it. Even at relaxed resort riding, I wear one (mostly, exception is to let my glorious mane go free).
My logic is this - if you're doing shit in the park, you're going to fall on your head sometimes. If you're skiing out on runs, theres a good chance anything you do wont incur injury, but its the 100 other gapers and idiots out there going 40 mph with pointed sticks that I dont trust. Yeah, a helmet doesnt make you invincible, but it gives you a better chance than without one. Its a benefit that completely overshadows whatever disadvantage (if any) there is to be had.
But again, our sport is called "freeskiing" last I checked. You dont have to do anything. Its nobody's responsibility, as there are no real rules or regulations, save contests. So, whatever, if you dont want to wear a helmet, go for it, but I really cannot see the logic behind not wanting to have one on your head.