Have you looked at the way schools are built?
I got to looking at the schools in our area and trying to figure out how many men it would take to "protect" the children there.
Especially that three story one with the long halls. How long would it take one man to run the length of the hall, maybe even run down two flights of step?
Look around at your schools and see how many police we would have to hire.
The days of the one-room school house are long gone.