I really feel for those who are on the dining plan and can't get into a TS restaurant. However, if you really think about it, what in the world made them think that they were just going to walk up and get a table? I mean, here you are in a vacation spot with a limited number of TS restaurants in the parks, TONS of people who eat in the parks for various reasons (don't have a car, don't want to leave just to eat, kids are hungry NOW, etc.), and only so many tables at these restaurants. As someone who lives in NYC said, you just know that the reservations at the good places are going to be made in advance. Heck, we can't even go to a place like Chili's (not high on my list of culinary masterpieces) without waiting over an hour on most nights and some places are even taking priority seating reservations in advance.
I understand that some people don't like to plan things like meals down to the minute since this is a vacation, but this isn't like any other vacation. This is Disney. I wouldn't go to a foreign country without doing my homework on food, customs, etc., so why would I go to Disney without doing the same? It's poor planning, IMO if you complain about the situation, but you didn't even attempt to research it in the first place. I really feel bad for the kids in this situation, though.