The mayor called the order unprecedented and said anyone who could leave the city should. He exempted hotels from the evacuation order because airlines had already cancelled all flights.(emphasis mine)
Gov. Kathleen Blanco, standing beside the mayor at a news conference, said President Bush called and personally appealed for a mandatory evacuation for the low-lying city, which is prone to flooding.
This happened on August 28th. Before the hurricane had made landfall. So, without Bush's prompting of seemingly passive (and perhaps incompetent?) local government officials, how many thousands of people would have died?