Well, there was advanced notice, but it was probably only about 24 hours. The thing just ballooned out of control (meaning it went from a minor hurricane to a Category 4) overnight on Saturday (I think), and it hit on Monday morning. In order to round stuff up, get it in there, and then get out of there in that time frame could have been a problem.
Yeah, I think people (yes, children also) are starving...I just saw it on the news; of course they show that sort of stuff. People were looting parts of the Superdome that had food/water out in the open. There was also a ton of stuff behind locked gates. I wouldn't be surprised that those fences get cut up and broken into soon.
As far as people getting out of there...the only explanations I would have would be that they either a) didn't have a car because they live in the city and use public transportation, b) didn't have anywhere else to go, or c) didn't have enough money to get out of there.
I think I would have tried to find a way out of there...even if I didn't have money. They said this thing was going to destroy everything, and it seems that it has.