As far as I remember, not too often. I did have a permission to look at the book in one history test aeons ago. Also, I have accidentially seen another student's test paper and then wrote down the same because my own memory was refreshed, but that's probably ordinary. I would have had a change to write cribs in Japanese but never did. The only one I remember was when I was 13 and wrote on my eraser '1848', because I knew Year of Revolution would be among the questions.

Have you ever skipped a reply because it was too long?