It brings a host of other problems, though, like the inability for two people to play two completely different games at the same time if they were purchased on the same account.
Actually, you can use offline mode to get around this, it's actually even possible to play some games multiplayer over LAN with two computers on the same account... not that I've ever done that.
We all agree on the necessity of compromise. We just can't agree on when it's necessary to compromise. -- Larry Wall