The feature these notes speak of is indeed included with iOS 7 (see: Activation Lock), added by Apple to help cut down the turnover rate of stolen or otherwise lost phones to thieves. The notes handed out by the NYC Police Department also suggest that users register their devices with the NYPD’s Operation Identification Program. This program is outlined by NYC.GOV in their Crime Prevention program listing as follows:
Operation Identification is offered free of charge by the New York City Police Department. The program involves engraving an identifiable serial number with the letters N.Y.C. on all portable valuables such as computers, fax machines, copiers, etc. and registering only the number and the owners name and address with the Police Department.
This program can be implemented by contacting your local Precinct’s Crime Prevention Officer. The officer will loan you an engraver, which is used to mark all equipment. Benefits from this program include:
• Special New York City Police Department decals are issued which are affixed to windows alerting people that all property contained within, has been registered in this program.
• The marked property is more difficult for a thief to sell.
• Stolen property in the possession of a thief is easily traceable to its rightful owner.
• Found property can easily be identified and returned to the rightful owner.