Not quite. The forecast models first showed a potential for a New Orleans hit on Friday afternoon. The NWS finally shifted their forecast late Friday, and first issued a hurricane watch on Saturday. By my calendar, that's under 3 days, and closer to 2.
Further, at that point, they didn't have a large site to put them (up until late Sunday, most of Louisiana was in the bullseye). There's a major difference between simply telling/ordering people to go and providing the means for them to go. Providing the means also implies that you'll take care of them. Now, they could have gotten a hold of the Texas governor to get the Astrodome or someplace else to use as an evacuation site, but that's now hindsight.
Yes it is. Deciding when to leave is always a judgement call, and mandatory evacuation is a public problem, not an individual decision.
But I do question the need to have a place to end up, at the time you depart the point to be evacuated. As a matter of fact, these folks are in a temporary location now, with final destination uncertain. They'd be better of in a different temporary location, one that isn't flooded, even if the final destination is unknown.
But don't you go with the "worst case scenario" and have a plan blueprint?
Sorta like when you're late and you think you might be pregnant?
Or if you are a lousy cook, having a fire extinguisher under the sink?
NO officials have known for 200 years that the MS river is on one side and Lake Ponchartrain on the other - those levees were clearly "at risk" as were the pumping stations.
Having a back up plan is not rocket science.