Seems silly. If she died 6 months ago before voting was open, maybe... but if she died after she voted... she voted. If you had a heart attack in the booth on election day, your vote still counts.
I think my hang up comes that there's an election Day...that's the day the election happens just like Christmas has a day and your birthday is a day. If you die before 2 out of 3 of those things you just miss it.