People should carry weapons with them. Engineers can make smaller, lighter, safer, and less lethal weapons. It has to have the stopping power of a gun, capacity to be useful in a long firefight, and it needs to be readily accessible. The problem is not much is going to match a gun. Schools could install gun detectors or have armed guards, but they will cheap out and not do anything. People need to learn to defend themselves. In most mass shootings, anti-gun people want to blame availability of guns. But what about the ability to walk into a school with six guns unchallenged?