Except in the issue of throwing food away (I want anything not eaten to STAY in my son's lunch box)... absolutely NO. I do not want anyone having anything to do with my son's food or eating habits.
Many, if not most, people have VERY strong opinions on food. I don't want other people's prejudices and preconceived notions about food pressuring my son, especially not adults he would want to impress. Of course there will always be peer pressure, but it's a level playing field... having an authority figure say something is *entirely* different than a peer.
When my son was in school, or now when he's in daycamps... I always pack about twice as much as I think he'll want to eat (ditto, we do large servings at home). The rule is, he eats as much of what he wants, and saves the rest. But I've had busy body aides tell him he has to finish ALL of his food, or not touch x until he's eaten y, or in any other way micromanage his eating or diet and it ***infuriates*** me.