The Police/Army/National Guard will force people to evacuate when it is clearly dangerous for people to remain in a disaster area - and such a danger exists in New Orleans due to water borne pathogens.
Tests show that sewage and dangerous levels of harmful bacteria are present in the flood waters. The flood water is sufficiently polluted to be a skin contact hazard. Disinfecting the water before pumping it into the lake or river will not be reasonably possible.
They are trying to convince everyone to leave. Those who will go willingly will be assisted out first. Eventually, they will have to evacuate the unwilling forcefully. This is very unfortunate, but clearly a necessity.
Bacterial infection from storm surge driven by the hurricane is already blamed for 5 deaths. Add to that coliform bacteria from sewage, bacteria from decomposing bodies, and hazardous chemicals and you have a serious health hazard.
Yes, it will work out in due time.
http://www.msnbc.msn.com/id/9156612/
http://www.msnbc.msn.com/id/9242497/
http://www.msnbc.msn.com/id/9241863/