Well, this action should certainly stop anyone else smuggling guns on board shouldn't it?
Good job he didn't have a catering van to hand.
It sounds to me to be an over reaction. I did things at 16 that were pretty crass and I can imagine that a stern lecture to the teacher in charge by the authorities would have got the message through strongly enough to the young lad in due course.
When you consider the remarks made by a pilot to a local authority recently and what some other pilots considered an over reaction by a court, this episode seems to be a bit of a storm in the teacup.