The problem for tourists is similar but on a smaller scale. NOLA is a tourist city. At any given time, there are lots and lots of tourists, many of whom arrive by airplane and don't have a rent-a-car. The 40 hour evacuation notice is given and you bascally have about half that time to make a move because the airports shut down 12 to 24 hours before the storm actually hits. You might even have less time if you are out and about and not tuned to a TV or radio when the evac order is issued. Now, you have to scramble to find a flight or a rent-a-car while in unfamiliar territory. There are only so many seats available and you are competing with a lot of other people for those seats, and while you might be able to get one, that's not going to help if you're traveling with a spouse, child or other loved one. The last thing you want to do is to go to the airport and take a chance because that particular airport sucks and who wants to be stuck at any airport for several days. So you decide to ride the storm out in a hotel. Not a bad choice and indeed, from what I understand, most of the hotels, particularly in the French Quarter and near the River, survived Katrina with only minor to moderate damage (mostly windows blown out on the upper floors, and minor flooding). Late Monday afternoon, after Katrina has cleared the area, people are back out on the streets. You can even find a few bars and restaurants open in the French Quarter. Electricity is out, but NOLA is a party town so no big deal. Then, at 2:00 a.m. on Tuesday morning, the levies break, and that's the begining of the end.
The stories that will be told by the tourists being held captive in the convention center are going to be sickening. The media will try to censor what's really going on in there.