You aren't allowed to have sponser logos bigger than a certain size on clothing, skis, helmets, etc in order to "maintain the spirit of the games". So they make their products stand out as much as possible - goku
Any athlete that is "sponsored" or "supported" by Oakley has neon green eyewear. This includes skiers, snowboards, xc skiers, etc...
Those that aren't "sponsored" have put tape over the logos of their goggles
I wouldn't really say it's for the "spirit of the games" though. It's more for companies like McDonalds and Coca Cola that have spent multi-millons on advertising. This way no other company gets prominant advertising - pipe_munky