This may sound stupid but why would a tourist have stayed in New Orleans after being warned the storm was coming? Its easy to understand why the poor and the old and even the regular citizens stayed, But even the dumbest tourist should have cleared out.
NOLA tourists are there to "eat, drink and be merry"... maybe too much of a hangover to get out of dodge...
There was a story in the DesMoines Register of a couple that went down there for a conference and when they found out it was time to evacuate, they went to get a cab to the airport and the cab drivers were charging $1,000 for the trip! They decided to stick it out! I think they finally got out of the city.