The kids need to learn how to eat in peace and good order. To wash up beforehand and settle into a *meal* -- not a gobbled snack -- with a blessing. At when done, to leave the table and floor clean -- and not some mess for "others" to clean, or worse -- to have to eat within, in those schools where there are multiple lunches.
In school, we always had good manners. If we didn;t, our parents were sure to hear about it. Then we got punished.
My instructions when schoolbound were very clear-—I better not do anything to make the teacher contact home, because if that happened, my parents said they would side with the teacher.
It was tough to take on such a united front.