Instead, label them BOX 1, BOX 2 and BOX 4 and put "geo-location circuity" (it doesn't have to work, just make it look like it could) in it and place those at various points in the school, preferably with visible wires.

Then you can claim that you were trying to build your own local mini-gps to monitor your movements throughout the day.

Same popcorn value, less time in prison.

You shouldn't be caught sitting in your comfy chair eating popcorn though...