Doesn't seem fair to me that the school is punishing her and her kids for the actions of another (her husband.) She's not forcing the school to go on lockdown when he shows up in the parking lot, he is.
It's not fair to the school either.
Why should the school have to hire guards to just to continue employing this woman. Why should parents put their kids at risk over this woman?
She chose poorly. It's not the school's problem.