Legality aside, everyone here has to admit that businesses that pop up exclusively to sell used products are essentially leeches.
Take GameStop. They buy games back for peanuts and resell them far above value. This is their bread and butter, from what I understand. They basically add no value to the market and take lots and lots of money from it. Why? They're completely worthless (I've never understood buying or selling from them when you can just use ebay for better deals on both sides.)
GameStop essentially makes their profit off of everyone else's hard work. And I can see why the people actually doing that work sucks. Hopefully the internet will put GameStop out of business and keep aftermarket sales as consumer-to-consumer instead of putting some congolmerate of inept employees in charge of it.