Well, since it can't be removed, some games like Team Fortress 2 have separate "beta" versions, despite being released, where players can test separate changes before they go live.
Although that probably wouldn't be ideal in this case because of all the free key giveaways. It would be a bit like getting too much of the multiplayer side for free, unless there's a a way to change the post-release beta to be "for those who bought the game only."
