I'm not sure how long this has been the case, but when I did my exams at the end of high school, the back of the cover page of the exam booklet always said "This is a blank page." We were explicitly told by our teachers not to write "not anymore" or "no it's not" on that page, as the assessor's had seen it so many times that we might put them in a bad mood. I'm not sure how much of an effect this warning had on us. Probably not much.

Anyone else have anything similar worth sharing?