Reply 220 of 225, by sliderider
This applies to digital games, but I don't see why physical copies of games sold with a Steam activation key wouldn't also be covered.
It won't work this easy. For that to work, the original owner must have capabilities to deactivate retail (CD key) games from an account, similar to Windows retail deactivation. And there're more troubles with DLC and account/VAC/other bans.
Not necessarily. Steam could do it entirely from their end by deactivating the game on the account of the player that originally used the code and activating it on the account of the player now in possession of the physical copy. If I have a physical copy in my possession, I have a right to use that game now and the license/activation key belongs to me. It no longer belongs to the other person. The fact that I have the physical copy in my possesion with the activation key should be all the proof that I need that I am now the owner of that license.