No, the nanny's accusation crossed the line. Nannies only need to take care of their children's safety and life. They shouldn't be involved in educating their children. It is the responsibility of their parents to educate their children. Their parents have no intention of hitting them. If you hit children, their parents will blame you. If you hurt a child, you can't take responsibility. Therefore, it is ok for children to be naughty and react with their parents. Don't discipline the children.