These are a great way to ensure that your 3rd, 4th, 5th graders are sticking with a chapter book. Once they decide on an independent book to read, you can scan the room to see if they are really reading what they say they have listed on their locker tag. Also, at the bottom of the tag is a place to keep track of what book they are on for the year.
You could also use these to help you keep track of novel study groups by having the students list what book they are reading for novel studies.
Print off your choice tags and laminate. Then cut in 1/2 and use double sided tape or heavy duty tape at the top and the bottom to firmly hold to the lockers. The students can use vis-a-vis markers to update their book choices that they are "currently reading" and hopefully will think twice before just grabbing any old book to sit down with!