In the first year ESL textbook I use, students are expected to listen to a conversation and fill in the blanks. It takes too much time for me so I made it homework for my students to fill in the blanks. The answers are on the next page but upside-down. Most students turn the book back a forth to read and remember a few words, fill them in, then flip the book again. This student sped things up by carefully ripping the answers out and holding them right side up next to the conversation. I approve.
No book, sleeping in the corner. I disapprove. No credit for attending this class.