Yes, in this case, when consequenses of fail so high, I would also just decided to study harder than try my luck and put my future on a bet.
Actually, I did 1 time like that.
After end of the shool we had shool-end exam, which is deciding whole your future. Points, you'll get, will or will not give you chances, to go university you want.
I decided to choose physic exam as my second one. Even though my knowledge in physic after years laming around were equal zero. I wrote all formulas and all examples of solving all kind of tasks on 1 giant A4 sheet. Giant for a note, which is have to be invisible.
I had same situation, as you wrote above. But also on the entrance in class there also were dudes with methal detectors.
I clearly remember how, when everybody turned away, I took out my sheet with formuls from my t-shirt and just put it right on a table and covered with empty shit above. When some time passed, I just put away clean sheet and pretended, that list with formulas is a list, where I was writing all the time.
At the end I've gp enough points to go university I wanted, where I'm successfully studying now.
Still suck in physic.
EPIC WIN.