I agree with you Mariana that physical force is warranted to protect a kid from danger.
– smacking a child’s hand as he reaches for a hot pot on the fire
– yanking and pulling a kid as he runs into the street towards an oncoming car
– holding down/physically restraining a child who is beating up his sibling
in these circumstances, talking nicely and discussing consequences just won’t do the trick when it is needed, although they can be used afterwards to avoid repeat behaviors.