Microsoft also announced today, its plan to build a "kill switch" into Windows Phone 8.1. Microsoft’s Vice President for U.S. Government Affairs, Fred Humphries, said that the company would add theft-deterrence capabilities to its Windows Phone 8.1 powered models, through a software update. This update would also be sent out to Lumia models made by Nokia prior to Microsoft's acquisition of the firm's Devices and Services division.
When Apple added its Activation Lock to the Find My iPhone application last year, it turned the latter into a kill switch. The results were seen immediately. According to the Secure Our Smartphones Initiative, in the first five months of 2014, robberies involving the Apple iPhone dropped 19%. In San Francisco, 38% fewer iPhones were grabbed during the same time period. In London, 24% fewer Apple iPhones were stolen in the first five months of the year
You can't argue with the statistics, which is probably why Google and Microsoft both decided to join Apple in making smartphones less desirable for criminals to steal.