In Washington, D.C., a series of crime-prevention posters show photographs of people using cellphones in public. In the pictures, the cellphones are overlayed with an image of a hundred-dollar bill and the tag line "This is how thieves see you on the street."
Phone users are also encouraged to install tracking software in their phones. Apple has the Find My iPhone feature, and a number of applications exist for other phones that allow users to remotely track a phone's position and delete data stored on the device. They require the phone to be switched on and connected to a network, but often thieves don't immediately switch off stolen phones.
If a phone is promptly reported stolen, police can sometimes locate the device and the thieves using such applications. "As with any security, there is no silver bullet, there's no one thing you can do," said Mahaffey. "But that doesn't mean we shouldn't do it. We should continue to find better ways to solve these problems."