Cheeky. Is that okay?

A teacher taught the laws of washing hands, etc., in his class.
And he said that if they forgot to bring a knife or salt, etc. to the table
It is permissible to tell household members to bring a knife, salt, etc. because these are necessities for the meal.
He added that he believed that if there is a child who is disruptive and does not allow the meal to begin in the village of Da'at, it is also permissible to scold him, such as "Cheeky" or "Calm down" in order to allow the meal to begin.
The parents complained.
The teacher claims that it is true that this is not written in the books of halakhah, but it is the reality that is more common in many homes to begin a meal.

Who is right?