Exam Interlude

Is it bad that I wanted to offer as a bonus question an over/under bet for my students about what time the late person would appear for the final exam? As a side bet, we could have tried to determine whether they would have brought a writing utensil or not.

I think it would've worked, though you could only do it once before someone tried to fix the bet. And, of course, there's the dubious nature of it...