I think all these shootings are happening because Kids are getting idea's that this is how to get attention. Not only that but the availability of weapons is too great and the emphasizing that weapons and violence is the best way to get rid of your problems. I grew up in a violent home, all us kids were violent towards eachother, and very destructive because we weren't taught that violence isn't ok until we were much older.
When your older it seems ok to see what happens with violence because we can I guess digest it better. But if you let kids know from the very first of that behaviour that death, serious injuries, and even prolonged internal injuries can occur from it. Give them real life examples, show them pictures of people brutally beaten and let them know that violence can in turn do this to them.
May seem like shock treatment, but I would bet that gunnings and bombings would be less idealistic in the minds of students. Of anyone really if they know what can happen both with the victim and the offender.... scare the violence out of em'.