In the end
the purpose of a voting machine is to enable fraud. EVERY mechanical voting machine was known to be easy to "adjust".
The difference, of course, is that with software, you can do all of it at once. And trapdoor the software to "correct" itself after the fact.
Every time this discussion comes up, the printed paper for the voter to view comes up. I've pushed it myself. The more I think about it, though, the less I like it.
Just do the hand count. The republic you save might be your own.