I'd be surprised if schools with metal detectors don't have active shooter drills. Mass shooters aren't deterred by metal detectors. They show up armed and walk

I'd be surprised if schools with metal detectors don't have active shooter drills. Mass shooters aren't deterred by metal detectors. They show up armed and walk into the building shooting. Metal detectors are better at preventing situations like gang violence where rivals carry every day "just in case".