Of course it's a great idea. Just like if everyone was issued a gun when boarding an airplane there would be no more high jackings. Just ask Archie Bunker. He had it right.

Something we should remember in all of this. If there were armed teacher at Columbine, there would be a few kids still around. The wacko's that want to shoot up a place and then kill themselves still get their wish when there is an armed citizenry, just a lot less innocent people get shot in the process. You will note that many of the shooting have occurred in areas where there has been a prohibition against carrying a weapon legally. The prime support for the allowing people who are licensed to carry to carry a weapon is the shooting at a church in the southern states; the perpetrator was stopped with minimal loss of innocent life.

I know, to our Canadian sensibilities, allowing ordinary people to carry weapons for self defense seems just so wrong. But part of me wonders at what point it became a bad thing to stand up and actually fight for whats right? Sure we protest, and write letters to the editors. We blog, and demand politicians write new laws to make whats already illegal more so. Most of us will dial 911 while peeking out through the curtains when we see something going down in the street, but how many take the initiative to actually step up and help out in a meaningful way? Not that I'm saying we shouldn't call the police, but once that's done what more can you do? We seem to have developed this false impression that the police will always be there to protect us. And their visible presence will deter crime while they're there. But as dumb as most criminals are, they are smart enough to look around for uniforms and badges before doing their thing. (Usually) So 99% of the time police spend dealing with crime is after the fact.
I know a lot of the fear surrounding firearms is the possibility of innocent people getting caught in the cross-fire, but most occurrences that require that level of response involve a lot of innocent people getting hurt anyway. Would a tactical response from a staff member saved lives at Columbine or L'Ecole Polytechnique? An honest answer, regardless of your feelings, would be yes, it probably would have. Could others have been caught in the cross-fire? Sure, but one or victims of defensive fire (I can't quite call any shooting "friendly") may have saved many more random victims lives. I know I make it sound cold, like its just a numbers game, but I'd rather grieve for 5 than 25.
Teenagers really don't have the skills to be armed and in public. But if adult teachers are trained and capable, they'd have my vote. Who knows, the fact that some may be armed might be enough to discourage the next college or high school shooter.

When you know that the states which have concealed carry permits and laws also have a lower rate of violent crime, including rape. It may sound barbaric, but it's actually a game of odds:

I'm a whacko intent on committing a murder or rape. What are the odds that I'm going to be successful if any one of my intended victims or a bystander has a concealed weapon and is trained to use it.

Would I agree with kids having a concealed weapon? No, but then again, I'm not sure that kids COULD GET a concealed carry permit under those laws. What I would agree with is a properly licensed and permitted user in the classroom, and the odds that few gun-toting maniacs would get past the first classroom if there were even 1 permitted teacher in the school. Problem is that it would be rare to find a gun that would go with every handbag and shoes.

:)