Learning Make-Believe Truths

I brought some work to the local Starbucks this afternoon and the shop is made for group sitting. About half the available seating is made up of long, narrow tables. They work great for Mom groups and police officer get togethers but they are a little weird for strangers perched next to one another. Today I was seated just kitty corner to a 7(?) year old girl and her grandmother. The young girl had as a snack a wedge of the blueberry coffee cake. And I couldn't help but notice how she ate it. Loudly. With open mouth smacks while talking. Out of the corner of my eye I could almost feel the fistful of cake go in and then half of it falling back out again.

Now I am not perfect when it comes to eating food and talking. Within the last half an hour I have proven myself quiet inept in such food/talking logistics but it got me thinking about the complexities of dealing with children. As a stranger, I kept waiting for her grandmother to tell her gently that it was, well, really gross to eat like that. (More like, "It isn't polite to eat with your mouth open.") They were both clearly well groomed women. This young girl is going to join a sorority some day and be part of Young Business Leaders of America. Wouldn't she just figure it out on her own? Or is it someone's responsibility to tell a child when they are or aren't fitting into the society's modes of acceptable? Or should parents just let their kids grow up without constraining them to all these socially-structured rules?