You could require that the game is disabled for user A before it gets enabled for user B. You don't need to make it *easy* to transfer ownership, just possible.
But if the device is never connected, we cannot disable it.
So we would be forced to tell the end user that he must connect all devices and wait for confirmation before the sale could go ahead.
Then we are into the situation were the end user may have lost/sold/traded in the device, etc.