That’s why you’re supposed to have paper backups. And you audit things.

Edit: I think you could even get a real time audit and still be electronic with backups

1. You go to machine and vote
2. It prints off a copy of what you voted and records it (this is the primary vote count)
3. You verify the paper ballot print off and take it to a second area to be recorded and kept for audits.
4. Put ballot in second machine which validates and counts the vote and externally shows a counter increase on the machine for votes counted (not who) so you also know this machine counted it for a total.

So now you have the proper vote tallies from 1. The audit of the correct amount of total records from 4. If there’s any cause for concern or for auditing, you can manually count the paper ballots.