That doesn’t answer my question...
Upon further review...
You are correct.
Though the RIGHT to bear arms is a right. To conceal or open carry requires a permit. The school had no idea if this person was permited to carry, and so had the right to question or restrict said person. Likewise, police also had the right to detain for verifying purposes. The same as stopping a driver of a car and checking if they have a valid drivers license.