Way to Stop Students from Deleting the login boxes?

Hi everyone,

I had my first case of mischief with the chromebooks today. One of the students in another class deleted the login box of another student in a different class. As we share chromebooks, often one computer will have 2 or 3 login boxes for each student that that computer is assigned to. While I was able to catch the student who did it and while I know that none of the information associated with the deleted user login box actually gets deleted, I am wonder if there is a way to keep students from deleting other students login boxes.

Cheers

Ian