This will be routine in close, hotly contested elections with operatives who believe they can acheive political goals via weak election procedures.
The "found" ballots might either be fabricated and introduced into the mix for the desired result, or be ballots believed to be in the opponent's favor that were "inadvertently stored in the wrong closet" - as may be the case here.
The sensible thing will be to produce serialized copies with strict depositing controls. There would be no ballots to be later found.
A republican and a Democrat representative, approved by each party, should be handcuffed together at each polling place. They should each accompany every ballot cast in their voting place to the place where they will be counted. After recieving a receipt for those ballots, the people receiving them, also handcuffed to a person of the opposite party, should then deliver them to a secure room where they would be tabulated......by a group of equally divided approved counters. Perhaps they could come up with at least a reasonable total....
Please explain what you mean by “serialized copies with strict depositing controls”. That term is not one I’m familiar with.
Thanks in advance.