What about 1 time use codes many console games come with now? I can see the multiplayer codes being safe as they can claim you are purchasing access to the serv

What about 1 time use codes many console games come with now? I can see the multiplayer codes being safe as they can claim you are purchasing access to the servers. But what about codes which unlock extra characters or other parts of the game, such as the Catwoman code in Batman Arkham City?