I seriously don't want to step on anyone's toes but I do think a few people here could use a little reality check.
I'm all for being a responsible person and preparing yourself for possible contingencies but that's no reason I would ever advise anyone to wear a kevlar-lined backpack. No more than I would wear a helmet every day because a roof shingle or a meteor fragment might fall on my head. If I wanted to plan for every contingency I would eventually need to encase myself in armor from head to toe, wear a life jacket because the polar ice caps might melt, reinforce my car with bulletproof glass and armor plates, avoid all processed foods because they cause cancer, bath in bottled water because terrorists might secretly poison the local water supply etc. etc. All of which would quickly ruin my finances and mental health.
Second, there's simply no way you could compare an American classroom to soldiering in Iraq. If you are so out of touch with reality to draw such a comparison you have no idea what it's actually like to be in a fight, let alone be in a war zone. We should consider ourselves lucky that we still live in a comparatively very safe society. If you think otherwise you should perhaps go visit some third-world country one day.
Third, what possible use would a gimmick like a FlakPak be (I'm only using this as an example, there have been lots of similar ideas proposed in other posts, too)? If I'm sitting in class and a madman comes in guns ablaze the last thing I'd want would be a backpack on my body. I'd much rather take my chances and either dive for the window or take on the bad guy up close and personal. Which takes a lot more guts than most of us could possibly imagine though, regardless of whether you have a gun, knife or just your bare hands. Again, it's all about the mindset, not tools.
Please don't get me wrong. This is not meant to be a personal attack aimed at anyone in particular. I just think the general public would be a lot better off using some common sense instead of falling for the hype. If you are concerned about your safety it would probably be a better idea to get in shape, do some boxing or judo, maybe a good self-defense class, learn how to shoot and run fast if necessary...
But above all avoid unnecessary paranoia. I was under the impression that this is not a survivalist forum but a place where one can discuss realistic survival techniques. I hope it stays that way.