I have 2 perspectives:
1-As a student. From middle school at least through high school and college. I carried at least a SAK and depending on what year a 3-5in lockback folder. I did this in the states of Washington, Connecticut, New York and New Jersey. I also brought shotguns/rifles to school and left in my car during hunting season.
2.-As a former Florida Juvenile Probation Officer and former Florida teacher. I find that the biggest problems in the schools are twofold-- the school resource officer and zero tolerance. The SRO has to justify his role there so he always wants to get kids for weapons and/or drugs. A knife/drug brought to school is more often then not a school issue it is not a criminal justice issue. If a kid brings a knife to school then talk to him---if hes a good kid and has fair reasons let him keep it.
I saw daily arrests for kids that were brought up on Battery of a Law Enforcement Officer because he got hit when breaking up a fight---gimme a break--of course your gonna get hit breaking up a fight.