The reason Badspot looks down on key resale(Or, at least, why account resale is frowned upon in general) isn't just because he doesn't get all the money - It's also partially because it's easy to get ripped off buying a used key because bans and admin rights will still apply, as well as linked forum accounts(which may or may not be accessible or usable). In most cases, especially with old keys, you're probably getting ripped off because you're getting a less functional(in that sense) key at a higher price.
