Yes I am sure. There are countless videos on YouTube dealing with rigged voting machines. I could not find the one that dealt with the Scantron counters being rigged, but I too was a little surprised by that. With the kind that teacher use the individual scantron is marked as incorrect and some tabulate the score and print that.
The ones used in voting store a running count on a card which is uploaded to he central computer. The problem is in the card that can be easily rigged.
Not the one I was looking for but....
One of many videos showing how to rig voting machines.