That's a possibility, but not necessarily the case.  If Dad makes enough for everyone to have a generous helping, but kids take double a normal helping, & worse, take a couple bites, decide they don't like it, & trash it, that's a problem. And yes, we are in a social group where this very thing happens.  Our host will cook several racks of ribs, the rest of us bring side dishes, plenty for the entire group.  But there are a couple of kids that will pile their plates to a ridiculous level, eat a few bites of some things, and not touch others (I have seen one kid try it, says "Ewww!" & that's the end of anyone else trying theirs) & leave a piled up plate on the table while they head off to play.  

There's no problem with people eating, but there's no reason they should take huge amounts before everyone has a turn, and there's nothing wrong with teaching kids to take a normal amount to begin and come back for seconds after everyone has their food, and they know what they like.