I was in a Taco Bell yesterday. I don't expect fine dining there at all. Yet this one little girl was talking very loudly (borderline yelling) and the mom just kept talking to her like it was normal. Then she decided the booth was a playpen and started climing all over it. I guess some people just think I'm a Nazi but I guess I have standards and expectations that I'd like my children to aspire to. Not disrupting the lunch of everyone else in the resturant is one of those.
I'm not saying don't talk, I'm saying talk at the appropriate volume level. I'm not saying don't play, I'm saying play in the appropriate locations. I'm not saying don't do anything at all, I'm saying as a parent you owe it to your kid to help them learn the appropriate behavior for the appropriate setting. And if your kid can't handle it (for whatever reason, maybe a medical condition) don't put your kids in a situation where they will fail and drive all the other patrons bonkers.
Watching kids play, truely play, with wild abandon and enjoying themselves at whatever interests them is a beautiful thing. All I'm saying is that some parents to a poor job of actually allowing their kids to play in the right environments (over protective, don't allow contact, avoid competition) but then let their kids play in totally wrong environments.