I did the same thing at my school, besides switching the left and right buttons' functions on the mouse. On one of the Macs I put a little piece of paper right between the clickable part of the mouse, so people thought the mouse was broken
. Did you know that if you press Ctrl + Alt + the triangle button on the old Macs and keep one of them held the computer will restart? Now, if you let go of the button held at anytime after restarting, the Mac will restart again. I restarted a Mac and taped the Ctrl button down with tape, with a note saying "Do not take off or all unsaved work will be lost." Some idiot took the note off, and you can pretty much guess what happens.
If you can read and understand what I just wrote, you are good.