Once bitten, twice shy. There is absolutely no chance Nagin and the other authorities/officials are going to take any chances on Rita. Therefore, they've just announced that they're suspending re-entry into New Orleans.
As ever, I came away uncertain what that means for Algiers, which was opened just this morning. Can they continue to enter? Seems unlikely, yet some are already on the way, but haven't arrived yet. All I heard about those already there is that people who have already returned need to "be flexible". Hopefully some clarification will be forthcoming.
If Rita turns northward, Nagin said one of the projected trajectories suggests the storm could pass to the west of New Orleans, leaving the city on the more dangerous eastern side. Any sign of a northerly turn will likely result in a full evacuation (assuming they leave it that long).
So - everybody's playing the waiting game again...