Makes perfect sense. If they have no problem arming commercial pilots to protect the plane, they should be greatful to those willing to be armed to protect the school.
Yes - and I think stewards / stewardess should all be allowed to concealed-carry (again, if they want to.)
Armed pilots aren't much of a deterrent, as they're locked up in the front of the plane now-days. But, I'd feel a lot safer on a plane if there was a 'armed guards present' sign posted.