The reaction to flying into the NFZ will depend on the reason that the NFZ exists. If you fly into the NFZ over Disney World, the penalty maybe won't be as severe. If you fly into the NFZ at DC, you most likely will be arrested. I witnessed first hand what happens if you fly into the TFR that follows the president. I had already landed because I knew about the TFR times. Another pilot apparently didn't check the TFR's and took off into it. He was arrested.
^This.
First, I apologize to the community for my uncivil tone earlier. By way of explanation, net "experts" that are anything but really push my buttons.
The fact is, how serious an NFZ violation is depends on the NFZ. The vast majority of NFZs are inconsequential if breached accidentally and briefly. For that reason, no punitive or corrective action would ever be taken, and no one here should fly in fear of such draconian law enforcement.
Similar to jaywalking when there are no cars in sight anywhere on the road. You simply are not going to be cited by an LEO for that, and if you were, you would very very likely win a dismissal in court if you pursued it.
Break the exact same law in the exact same place at the exact same time of day except with heavy traffic, and that same cop nearby is very likely to cite you, and you'd be held responsible in court if you fight it.
This is why we have judges and courts. To provide discretion, and apply reason accounting for mitigating factors in enforcing the law.
You should never PLAN to fly into an NFZ without prior authorization. However, if you should accidentally find yourself in a relatively inconsequential one, nothing is going to happen to you legally, and you should be able to fly out as soon as you know. That's what the FAA and the aviation community expect.
Alternatively, if a TFR is in place because of the president, I just wouldn't fly anywhere near there at all until it was gone.