I have heard tell of a couple professors at my school who do this. (Including the one who wrongly accused me of shifting the furniture in the classroom we both used so that I changed classrooms.)

ETA: Grading--I gave my medical roots students condylocele, a swelling on the knuckle. But the textbook also says condyl- is knob, so I'm getting a fair amount of "swelling knob" responses. Which, um, makes me think of another part of the anatomy altogether...