I have 2 kids, and the thing that grates on me, is how unfair it is on the CHILD. Children are not just learning to behave - they are forming their self-concept. They do not know what they need, they do not know their limits, and they do not know how to manage themselves.
If you constantly set them up for failure by putting them in situations where they are exhausted, overstimulated, or developmentally incapable of behaving appropriately, then you are teaching them that they are failures, people don't like them or want them around, and they are the source of constant frustration/embarassment to their parents. And then they will live "down" to the expectations they were set. So, so, unfair and cruel.
I think regular, small doses of selected "grownup" venues can be great for teaching and motivating kids to appreciate manners, culture, and the wider world. But it is the parents' job to meet the child's needs for rest, physical activity, food, and attention span - so that it is a pleasant experience for the family, and for the people around them. I often tell my girls, "I am so proud of you, I can take you anywhere!" But I don't. I take them to places where I have planned my resources, my time, and my exit strategy.
I get so sad to see kids misbehaving and melting down in inappropriate places/times - because I see a kid whose needs are being ignored.