If a school were to apply the exact same policies to teachers as the school applies to students, the wrath of God would land on that school.
Such policies violate labor laws, they violate the right to due process, they impose unconscionable restrictions on citizens without any plausible cause.
The US Supreme Court has ruled over and over and over and over and over that students ARE citizens and that they are not wholly stripped of the rights of citizens just because they enter a school. Especially if that school attendance is mandatory under the law.
You can't train people to be good citizens by treating them in a way that is ILLEGAL to treat citizens, then claiming that your policies override every statute and the constitution itself so they're perfectly legal. They're not.
"Whoever, owing allegiance to the United States, levies war against them or adheres to their enemies, giving them aid and comfort within the United States or elsewhere, is guilty of treason and shall suffer death, or shall be imprisoned not less than five years and fined under this title but not less than $10,000; and shall be incapable of holding any office under the United States." --- 18 USC 2381.
The USA is governed of The People, by The People and for The People. If The People are the enemy of the government and the government uses military tactics and weapons, then they are traitors and disqualified from holding any position in the government.
Given how broad conspiracy and accomplice statutes and case law have gotten of late, it's entirely possible that even the janitors wold be guilty of treason.
You'd be surprised how many terms in common usage such a ban might sweep up.
Scum bag, for example, compares the target to a used condom. Scum has a similar meaning. A nice person is someone too stupid/retarded to be mean to people in the original meaning. Retarded used to be a clinical term before it was an insult. Most people would be astounded what a properly programmed bad language filter might block.
Oddly enough, that sort of situation is the only one I've ever heard of where a high court has ruled against police.
In Plummer v. State, the Indiana Supreme Court basically ruled that it's legal to shoot and kill police (in that case a town marshal) if the officer attempts to summarily execute you instead of making an arrest and the alternative is your own death.
It's not binding anywhere outside Indiana, and AFAIK the US Supreme Court has never heard a similar case, but Indiana common law is the same as US common law.
There's no guarantee SCOTUS would rule the same way if such a case came their way, but it's common sense that you can lawfully defend yourself against a second degree murder attempt.
It might not have even been that overt an act on Mr Noriega's part that "provoked" the agent to open fire.
If someone screeches to a halt next to your car, you're going to turn and look. A bad guy HAS to turn and look in preparation to drawing and using a gun, if he expects to hit anything. Therefore anyone who turns and looks to see where an unexpected loud noise came from is intending to murder a federal agent, rendering the agent justified in shooting in self-defense.