I'd never thought about it until I saw a long thread here this morning, but there's apparently quite a bit of furor as if to the absentee ballot of a known deceased person is valid....
I for one have no problem with it. If I walk into a polling place, vote, and then get hit by a car, should they toss out my ballot? How can they practically do that? Well, I don't see the situation being any different with absentee ballots or early voting. Yes, it makes it a bit more likely to occur, but really it's still a very small number.
Besides, the real fraud is not people who die after they cast their vote---it is people who vote on behalf of people who are already dead. That's a far more pressing problem.