I am no lawyer but under US law, a company can refuse service to any potential customer and for no reason at all as long as it's not based on race, color, sex, or religion. Under this, they are perfectly within their right to cancel orders or deny future access to Nike products to anyone. Limiting quantities and charging a restock fee is also under their right as long as it's stated somewhere publicly accessible and stated in their policies, in this case their website. Of course if you or I need a reason, they can just say it hurts their brand by not being able to provide their product to their customers. Probably something like that.
First sale doctrine has to do with you actually having the item in question in your possession, by legal means of course. After you buy something, in this case shoes, first sale doctrine kicks in and the original company can't stop you from selling it to someone else. It's hard for first sale doctrine to go into effect when the company can refuse to let you buy their item. This is why Nike is tackling this issue in the "backend" so to speak by stopping would be resellers before they buy and not the "front end" trying to sue known resellers.
All in all I think it's a good thing they're cracking down on resellers, I can finally get my hands on some pandas...maybe lol.
