Apparently, it worked because in today's USA Today, there's an article that the 26 estates of the wealthiest New Orleanians are virtually unscathed by wind or water damage. Of course, it could also be that the old white men who built these lovely homes in the nineteeth century, knew that one did not build below sea level.
Incidentally, the people in the "Uptown" (really!) section of NO evacuated to tough places such as Aspen, but they helicoptered a Houston-based private security company in to protect their property and there was NO looting. Now that's the way to handle a hurricane.
They COULD consider raising the parts of the city that they're going to rebuild. Do you think that would be too expensive? It wasn't too expensive to allow it to sink.