If, indeed, the kid willingly and knowingly broke a school rule as important as this, I think we can agree that some punishment is in order. Was there no punishment between “nothing” and “explusion” that could have been applied?
The Wolf
Excellent point, and the answer probably lies in the numerous factors which were not specified in the OP.
Also keep in mind, that with three weeks left to go in the school year (and in this case, until graduation), the students feel like they can get away with anything, so the response might be different than it would be if it had occurred in the middle of 11th grade.