-Little to no resistance? Sorry but the data doesn't support that for school shootings.
https://www.ojp.gov/ncjrs/virtual-l...hool-officials-and-fatal-and-nonfatal-gunshot
However,
the data suggests no association between having an armed officer and deterrence of violence in these cases. An armed officer on the scene was the number one factor associated with increased casualties after the perpetrators’ use of assault rifles or submachine guns. The well-documented weapons effect explains that the presence of a weapon increases aggression. Whenever firearms are present, there is room for error, and even highly trained officers get split-second decisions wrong.
Prior research suggests that many school shooters are actively suicidal, intending to die in the act, so an armed officer may be an incentive rather than a deterrent. The majority of shooters who target schools are students of the school, calling into question the effectiveness of hardened security and active shooter drills.
-I agree. Teachers have a stressful enough job already. If you want security guards, hire security guards, but it's not a great solution either.
-It's not reasonable when the vast majority of the workforce doesn't want to work in an environment where a secret amount of their colleagues may be secretly armed, and they have no right to know who, or how many. This doesn't even take into account parents of students who disagree with this and would also have no right to know if their children's teacher was carrying a concealed weapon while teaching.
-The factors involved in school shootings is something for another thread.
-Well you can, as I posted above. Even armed guards don't necessarily prevent school shooting deaths, so why would a few teachers armed with handguns?