>>*not actually punched, they worked like scantron sheets
>
>Inconsistently...

I recall a scandal with scantron machines (or perhaps a off-brand version thereof) about the time I was in junior college.

It seems that the scoring machine marked a question as right or wrong depending on if the "hole" for the correct answer was filled in. What it didn't do was check if any of the incorrect holes was filled in.

It didn't take the students very long to realize that, if you filled in all the holes, you'd get every question right... :)

Yes, in practice a solid-black answer sheet is something that would eventually be spotted by even the dullest TA; it was more along the line of a "cool hack" than a practical method of cheating. But it really makes you wonder about the rocket scientists that built--and tested--the scoring machine.

("Brain surgery? Not exactly rocket science, now is it?")