> If you turned in an assignment written in pencil, it was legit for the teacher to use their eraser and give you an F for turning in empty paper. (They never did this but threatened it a lot).

I find this slightly amusing/ironic because many (most?) fountain pen inks are not waterproof. I had a sheet of paper that was full of (fountain pen written) writing on my desk when I spilled a glass of water -- after the paper dried there was hardly any evidence that there had been writing on the paper. I know that's not the parent's point, but something turned in that was written with a fountain pen would be easier to remove: a teacher would just need to dunk the paper in water!