Betcha most parents don't even know how many entrances and exits are readily accessible in their schools and how easy it would be for anyone to take command by marching up to the office and sealiing exits. The only certain way to prevent it is to control initial access to the school and have some means of button that alerts law enforcement if security is breached. Question is, how secure do parents want their children to be in public schools and will they pay for whatever changes and charges need to be made to enforce it. All those parent-teacher meetings and programs at night with open doors are an invitation for those who do not belong there to get a birds'eye view of the building.
I can only use my school as a point of reference. We have a closed lunch which means that students are not allowed off campus during lunch. Largely we are fairly successful in efforts to keep them in, but it would be a lot more difficult to keep a determined and armed force out. especially if there was no prior warning. Then there is a large area of portable classrooms (my area) which sits along the perimeter of the athletic field. There are probably about 300-500 students and their teachers in these areas all day long. Each portable has at least two exits, but it would still be a hostage disaster.
Law Enforcement? After the debacle at Colombine, I seriously doubt that they will get the situation rectified in time. Trust me, I'd feel a LOT better if me and my best buddy (retired Airborne Ranger First Sergeant) had access (legally) to our firearms!
How secure do parents want their children to be in public schools and will they pay for whatever changes and charges need to be made to enforce it?
The Haitian parents of kids at my school can't afford to keep their kids properly fed and clothed!