The original point here was that there was overreaction to a tip. Are you living in the same United States I am, where tort law is completely out of control? Can you spell "liability?" If anything DID happen, and the school / cops HADN'T reacted swiftly and with the resources necessary to handle any potential resistance, the lawsuits would be in ten figures. Stop and take an educated guess about how much money is going to change hands after the events of this weekend over the negligence and unpreparedness in and around Fulton County GA.
In a post-Columbine U.S., the incident described sounds to me like a very normal reaction.
As far as the cops being over-gunned, I agree with the previous contributor who said that as long as it's legal for me to own it too, I have no objection to the police having whatever it takes. As for the creeping militarization of the police, that's another -and quite serioius- problem, but one that goes beyond the scope of this thread. The police should be prepared for any possible threat. This stems not only from the N. Hollywood / Bank of America shootout, but the "FBI massacre" in FL which occurred earlier, and which should have produced more changes earlier than it did. If that means cops taking kids out of classrooms armed with M-16s, so be it.