1. Mass murderers who plan on killing themselves after the spree are not deterred by posthumous legal penalties. Really. Trying to disarm everyone who can theoretically snap is impossible — witness the Russian cops doing mass shootings against the disarmed population.
2. Mandatory lock-downs deny escape to those whose only hope is being a swift and difficult target. Interior doors usually have glass sections and do little to stop armed intruders.
3. At the colleges where I taught in the past decade, about 25% of the teachers and engineering school students carried pistols, up to 10% of the graphic design students. When VT shooting happened, a co-worker said “Thank god our students carry! If this crap happens here, we can hide behind them.” Granted, I wasn’t teaching at a K-12, but the same reasoning applies to them. In a typical school with a hundred or more staff and teachers, it’s likely that a half-dozen armed first responders are on site, and at least one of them would be close enough to fight back.
This is linked over at mine. Well, actually I just linked the site, not just the post. The post I stole the picture from. The question to ask is, if you can’t have a gun why not have at least a well balanced knife to throw?
(a) because throwing your weapon at your attacker is risky, (b) because throwing a knife accurately is very hard, (c) because stopping an attack with a knife, especially if you’re a small and not very strong defender, is chancy, (d) because the gun-banners generally ban weapons of any kind, at least they do in Massachusetts, (e) and so on.
Then again, knives are a fine last chance backup. I’ve been thinking of getting one of these: http://www.hideawayknife.com/main.php