There was a time when the biggest school safety worries were someone falling off the playground equipment or a high schooler injured in shop or home economics classes. Parents sent their kids off in the morning concerned mostly about lunches, homework and paper machier science projects, not whether the school could be the target of a random attack by a gun-wielding thug. Then came Columbine, when two deranged students killed 13 of their classmates and teachers in a 1999 shooting spree at a Colorado high school.