They will learn a lesson from this...as they should.
I ALWAYS carried a pocket knife to school during my last 2 years in high school. It's the norm, or should be. This isn't an infraction, this is an outrage. The rule is an example of too much statist power.
The schools today would have crapped their pants if my buddy brought his revolver in to show the science teacher. Like he did circa 1976. And that was in a Democrat-controlled city.