As seen in the link below:
Multiple alpha players have already found that you can easily crash your game by teleporting or telekenisis’ing into a TP and rollback the save a few minutes.
This allows you to exploit things like rerolling runewords infinitly until you get that perfect roll. There are more than likely other ways to crash the game on command that would have the same effect. This type of exploit has also been known to be a popular duping method.
I hope Blizzard takes care to find and resolve all of these exploits; or finds a way to better sync up the client and server data so that when crashes do occur; rollbacks do not happen.