Police in the US have warned victims of iPhone theft not to take the law into their own hands, after a surge in the number of cases of people using IPS tracking devices to hunt down thieves.
Officers say that apps such as Where's My iPhone are increasingly used by people to track stolen devices themselves, without the help of the law, and whilst some report success, others come to grief when confronting criminals.
"This is a new phenomenon — it's not simply running after the person to grab the phone," George Gascón, the San Francisco district attorney and a former police chief told the New York Times.
"It opens up the opportunity for people to take the law into their own hands, and they can get themselves into really deep water if they go to a location where they shouldn't go."
"Some have been successful," Mr. Gascón said. "Others have gotten hurt."
Across the US, mobile phone thefts are on the rise, up 26% since 2011 in Los Angeles, 23 per cent in San Francisco; in New York City Apple products account for 18% of all grand larceny.
In the UK last year, an increase in the number of smartphone thefts was behind the first rise in property theft in 20 years, with 750,000 stolen according to police figures.
With resources stretched, police do not have the capacity to track down each thief, and have lobbied for 'kill switches' to be built into all smartphones, allowing them to be remotely disabled.
Despite Apple recently introducing the switches, plans to make them compulsory in California have ground to a halt in the state legislature, with the telecommunications industry opposed to them.
In the meantime, for many, the temptation to follow the blip on the map proves too strong to resist.
Last year, San Diego resident Kenneth Schmidgall lost his phone at a reggae gig and tracked it to a man on a beach. A video a friend made of the resulting fight went viral, but Schmidgall was accused of violent vigilantism.
In the UK, unlike the US, the police do not even use GPS data to track stolen devices.
"I can see no reason why they should not use GPS tracking to recover stolen property, but for some reason they don't seem to do so. It may be that they don't think GPS is accurate enough to be certain of the address," Iain Johnstone, of Tuckers Solicitors, told the Guardian.