http://www.nypost.com/p/news/local/nypd_apple_corps_PmTgzglh...
> Every time an Apple device is stolen, detectives attempt to get tracking numbers from the victim or online records.
> That number, known as the International Mobile Station Equipment Identity, is then shared with the officers in Police Headquarters who pass it on to Apple.
> The California-based company then informs the NYPD of the device’s current location — and it can track it even if it was reregistered with a different wireless provider.