Well, neither the AWB nor background checks had any effect on Columbine either nor would either. A straw purchase is not going to prevent a the criminal transference and use of a gun in a commission of a crime. The government can only punish the straw purchaser AFTER the fact.
An armed guard stopped a school shooting from becoming a massacre yesterday.
Yes, communities would pay for security with their taxes, primarily property taxes. Just like they do NOW.