I think there's maybe a little confusion here. There's 2 different types of used gear on GC's website.
The first you can find through the normal catalog. I think this is gear that people order and receive damaged, non functioning, or beat all to crap and decide they don't like it and send it back after abusing it. They then refurb it and sell it on the web as Used. I live in KC where the distribution center is and they used to liquidate all of this through a clearance center at the distribution center, and I used to get great deals on stuff, but they closed the store and now they do it on the web.
The second is that on GC's website, they have used gear that individual stores buy from customers and then try to resell. So yeah, 2 different beasts, and 2 different policies on how you can and can not buy and how you can and can not return.