I think that voter fraud is a lot more widespread than anyone thinks. What is to stop a college student from sending an absentee ballot to his home state and registering to vote from his college address, too? My Mom worked at a polling place Tuesday which had a huge number of college students voting and wondered how many of them were actually out-of-staters double-dipping.
I was around the UW campus during move in week and overheard a couple of those "register to vote" people telling students to do just that... vote absentee at home and vote here in person.