How many knives do you have in your school?
Dozens, and that doesn’t count the ones for knife-throwing class.
When I went to high school (70's) I probably carried my small swiss army knife in my pocket about 60% of the time. It was a "mini" with only two blades that was very handy. If I saw a teacher trying to cut something I wouldn't have thought twice about offering the pocketknife to them and the teacher wouldn't have thought twice about accepting it to do the job. It was as natural as a wallet, chewing gum, spare change or any other thing people carry around in their pockets. Now you get ARRESTED for it?