> Missouri prohibits such ballots from being counted if it is proven that the voter died before polls opened and the ballot envelope has not yet been opened.
It seems reasonable to me that to be an eligible voter in an election, you must be alive. A ballot filled out in advance is merely a piece of paper until it is officially cast by an eligible voter on election day. If a voter dies before the polls open and there is a system in place to detect this, their vote should not be counted because they are no longer eligible. Conversely, if the voter is alive even one second after the polls open, their vote should be counted.