I think the OP is specifically asking about an employee of the school being able to carry.
When I was a teacher I was given permission by the principal and superintendent to carry concealed at all times, which I did. That was the ONLY permission I needed. Granted, laws may have changed since I stopped teaching in 2018.
When I was a teacher I was given permission by the principal and superintendent to carry concealed at all times, which I did. That was the ONLY permission I needed. Granted, laws may have changed since I stopped teaching in 2018.