Harold TX ISD has the right idea. How many of us will be talking to our school superintendents? I know we have ONE campus officer to cover three schools. And while they're all close together (how far apart can they be in a town where you can go from the east limit to west limit in 5 minutes?), that's still a matter of minutes to get from one to another.
I had also read a proposal on another blog (sorry can't remember, tried to find it) that suggested a gun safe in the principal's office that can be opened biometrically by qualified personnel. Opening this lock would also automatically alert the local police. But while the people under attack are waiting, they would also be armed. Who was it that said "The best offense is a good defense"?
This is what I consider to be rational, logical discussion of securing our children.