"Unless you are the violator or perpetrator - there is no threat of deportation or arrest, as it relates to the New Orleans Police Department."
In the short version, the NOPD is no longer enforcing Federal immigration laws. While folks will scream about this, it isn't really a change. The only real substantive change would come if they announced they were cracking down.
This is simply a play to encourage more witnesses to come forward in a city that is famously short on witnesses. I do not think it will have the effect desired. For one, the DA's office could still report illegal witnesses and victims of crime to ICE if the cases ever make it to court.
Two, illegals are the most important cog in the United States' underground economy. Bosses can screw them over in wages and benefits, and they have no legal recourse if they complain. If they get injured on the job, they have no workers' comp. Forget healthcare benefits, especially for their children. They are often paid in cash, so there are no pesky payroll, income tax or any other necessary paperwork to file for their employment. They often keep their money in cash, because they can't legally open bank accounts, making them easy prey for robbery everywhere they go. (The home invasions in Coastal Georgia counties were both legendary and underreported.) Moreover, the increase the profit margins and enrich the most unscrupulous American business owners, and provide a fertile ground for gangs to establish racketeering patterns.
So yeah, folks with fingers in the underground economy will want to keep things this way.
Lastly, there are a lot of comments one the NOLA.com article about Georgia's illegal immigration crackdown. The Georgia policies that have been the most effective have little to do with local police practices in any county, and far more to do with the state going after businesses who hire illegals, which is a far more effective way to address all the concerns listed above.