iPhone thefts have been dropping dramatically in at least three major cities since Apple introduced its Activation Lock feature in 2013, Reuters reports. Specifically, the number of stolen iPhones in San Francisco has reportedly dropped by 40 percent, while the number of iPhone thefts in New York has dropped by 25 percent, and smartphone theft in general has dropped by half in London. The drop is believed to be a direct result of the anti-theft features…