I once wrote poetry in the margins of a geology test. (It was a rock identification test, and you had to wait for the person ahead of you to be done with the rock and pass it on. One slow person could delay the entire class.) That test, I assuredly got back; well, all he'd have to do was pass out the rocks in a different order next time. He also didn't own copyright on those poems, and indeed seemed pretty alarmed at them.
"Now everyone was giving her that kind of look UFOlogists get when they suddenly say, 'Hey, if you shade your eyes you can see it is just a flock of geese after all.'"
"You can't erase icing."
"I can't believe it doesn't work! I found it on the internet, man!"