Kepler
Cornell Big Red
Electrical cooperatives, still pretty common in many rural parts of the country, typically operate off of a system where members in defined districts elect a board member from their district to represent them.
Once I was asked to be a witness to the official vote counting at an electrical cooperative (it's a long story why).
They used the same system, with the ballot placed into the secrecy envelope, which in turn is placed into an envelope which is addressed.
First, I would guess that out of a thousand votes there were somewhere in the neighborhood of 25 that screwed that up. The most common mistake was simply omitting the secrecy envelope, but we had votes where the ballot was placed into the addressed envelope, and then placed inside the secrecy envelope. We got checks and electrical statements. We got secrecy envelopes correctly placed inside addressed envelopes, but then no ballot was put in the secrecy envelope.
It actually was pretty eye-opening, and definitely a head shaking moment for me.
Remember the bottom kid in your high school class?
That kid votes.