Unfortunately I have seen similar behavior with the parents sitting at the same table.
People obviously think - It's Disney World - my kids can do whatever they like. I am a lot more laid back at WDW with kid's behavior, but you know, when I am spending money at the nicer places and there are kids crawling on the floor, standing on chairs, and running around unchecked, it ticks me off. There just isn't much you can do about it.
These are the parents who will have problem kids later on, mark my word, and it is not as cute when they are teenagers. And they'll wonder how it happened - sad but true.