The information is shared with everyone. That's what's meant by data leak. Barn door open. Horse gone.

I use mail in ballots. It's fine. Errors and fraud will occur but the margins are small enough that they aren't going to swing outcomes.

These can be solved by requiring mail-in ballots be notarized in front of multiple witnesses

And there we have the actual plan. End mail in ballots because enabling people to vote is devastating to Republicans. That's why it's illegal to give water to people who wait for hours in queues to vote. Don't invest resources to make those queues short. Invest resources to make sure those waits are as unpleasant as possible.