A hack is a hack. Regardless. Latent prints are all over the place. Probably possible to lift such from the device itself. Which would be like locking your car then taping your keys to the outside. As for another hack, just a matter of time. Anything one creates, another can and will undo.
The majority of people who steal an iPhone aren't going to be determined enough to lift a latent print (which would probably be smudged. I can't see a SINGLE good clean print on my iPhone screen), make some sort of fake finger to apply the print to, and then get into the phone. No, instead they'll probably try and guess the simple 4-digit passcode. If your data gets wiped because you had that feature enabled, oh well. Or they'll reboot it into Recovery Mode and make it a clean install of iOS 7, which is what the whole push to update TO iOS 7 is about.
I wouldn't expect NYPD to be allocating any real resources to tracking phones of any sort. Any real big city PD has plenty of real issues in never ending supply to deal with. Robberies, big thefts, violence, domestic incidents, etc.
You'd be surprised. Just the fact that someone calls in to report their stolen iDevice takes Police Time and resources. Depending on the jurisdiction, it may be REQUIRED for an officer to go out and take a theft report. Due diligence. The "Find my iDevice" feature is
VERY useful. I've misplaced my phone before, as have some of my friends and family. All it takes is opening the app/webpage and signing in to your Apple ID, and you can see where your phone is, you can lock it remotely (if for some reason you happen to have a stupid passcode or no passcode at all), you can make it play a noise regardless of volume/silence options, you can have it display a message for whoever finds it, and you can even WIPE it remotely should you need to. Does Apple have the ability to track people's locations based on that? Absolutely. Are they likely to? Not really. Does the convenience and usefulness of such a function outweigh any potential downsides? HECK YES. Say your iPhone gets stolen while you're at a restaurant. You can pull up the location and discover "Hey! It's at so-and-so address!" Then you can call the Police and let them know EXACTLY where the phone is. This situation has happened in the past. Google it.
Now, Buffalooed, would you PLEASE quit it with the NSA Conspiracy/ColoCrossing Horribleness/Whatever the hell else? At first it was somewhat interesting. NOW, on the other hand, it has gotten to be ridiculous.