Well, a while back a LA poster noted that they may not have confidence yet that the levees are going to continue to hold, that there may be concern about liquification and weak spots. Remember, even without storm surge, most of the city is still below sea level, so a breach could still cause devastating flooding. I sure wouldn't let people back in until all the levees of a bowl where checked out.
good pt. It would be nice if the pumps were started too.