Since 1999 when two students shot and killed 13 people and wounded 21 before killing themselves at Columbine High School in Littleton, Colo., security solutions have been on the radar for secondary schools. In 2012 the tragic shooting of 20 first graders and six adults at Sandy Hook Elementary in Newtown, Conn., reminded schools around the country just how vulnerable they could be — inside and out — prompting renewed interest in lockdown solutions. But in the rush to placate parents and communities, many schools have put in place systems that were less than thought out. Many others are still in the thinking and planning stages.