Its just another law that will be enforced as strongly as the anti drug laws. Only difference is the real criminals are not the gun owners. I can see the police’s concern, just how many officers will they lose when confronted with a neighborhood of irate legal gun owners. The police and the national guard are filled with civilian legal gun owners. This is what you get when you have elected officials put in office by the uninformed voters.
To that point; perhaps groups of like-minded friends and neighbors could set up some kind of early warning systems. Use computer cams and microphones set up to live-stream from your house to the computers on your network of allies. When activated it would contact everyone in the network on their 'puters, mobile devices, etc. like a text message. Just a thought.