Under normal circumstances that is a good rule of thumb to live by. However, in the case of voting machines, it would be trivial to make the printed copy be extremely hard to forge.
I don't trust ballot boxes without a paper audit trail because I've worked with computers long enough to know that you just don't trust the things without auditing, especially when someone had something to gain by gaming the systems.
Amen to that. I am also an IT professional, and the fact that there was a known flaw which would permit after-the-fact manipulation of the votes is a big deal to me.