I'll (lightheartedly) come to their defense to say that this is how I and a lot of my peers made it through med school. The wetness of the page indeed unlocked some supressed memories.

I think it's a combination of a ritual and some sort of somewhat-more-elevated engagement (or wishing thereof) with the material. Somewhere between meditative ritual and attention aid. I doubt it helped much, if at all - except for Stabilo; they were the true winners.