It's often not allowed to carry in places like schools (varies depending on district or state). However, many pro-gun supporters make the argument that CC supposedly makes public spaces safer because active shooters don't really need a license to murder people anyway, so anyone carrying during a situation has more defense (just stating the argument, not certifying it's correctness). But I'm interested in hearing how often it's the case that some licensed idiot badly secures their weapon in a public space leading to an active shooter situation (and for this reason I definitely wouldn't trust students to CC. But I'm also not in favor of clear backpacks, as that similarly feels like a case of "solving the wrong problem").
Note that in most of the geographic US, concealed carry is the norm, not the exception:
https://upload.wikimedia.org/wikipedia/commons/8/8c/Conceale... (blue and green are either constitutionally protected rights, or the state is legally required to give a permit)
1. Active shooters, while rare, have completely eroded our trust in our fellow humans. Either a gun is safe to bring into a school or it's not. If it's not, then why do we allow open carry/concealed carry permits in public spaces? Active shooters have been both kids and adults. You might make the case that kids can't handle firearms safely -- though I was once a kid with access to firearms and I knew how to handle them safely. (Don't take this paragraph to mean I'm pro/anti gun control. It's just an observation)
2. Public Schools are public property. Private schools are private property. In either case, it's perfectly legal to have a surveillance system.
3. Parents feel more comfortable knowing the school has a means to keep their children safe. After all the school is responsible for the children while they are at school. Worse, should something happen to a kid on school property, there will be a lawsuit claiming the school did not do everything in its power to protect the children -- hence the need for surveillance.