Every school needs a properly trained person with a gun because if there isn't there is nothing stopping a man with a gun if he is at the school besides the cops that come five minutes later. So for five minutes that guy with a gun has free range. If there is a properly trained person with a gun he can stop him within 30 seconds and not only is it good defense but he will also likely deter possible school shooters. No matter how crazy you are you wouldn't want to enter a school knowing that there is a guy with a gun there who is just waiting for someone like you to come along.