Based on my experience with a few phones I own, there's a few things that could be happening here: It was mentioned the "SSID"/MAC address problem. It's possi

Based on my experience with a few phones I own, there's a few things that could be happening here: It was mentioned the "SSID"/MAC address problem. It's possible that they have a home router with its default SSID and are encountering a MAC address collision (assuming MAC address is always taken into account, which I'm not sure that it is). Their router is likely part of some database that the GPS uses when the phones enter an area with WiFi but no cellular service or line of sight to the satellites. I had a similar failure every time I went indoors to an archery facility I visited weekly for three months. Both my wife's and my phone would think we were a clear 30 miles away in another city the second we got far enough into the building to lose cellular service. I dug into it and discovered it was using WiFi APs to get location. I think the archery place has another location in that other spot, so it's possible they swapped WiFi gear at some point, but it's anyone's guess. Another possibility, hinted at in the article, is that there's no other location data available to the stolen phone (no mapped WiFi, no cellular service) but it has an IP address so the devices are falling back to Geo IP which is extremely inaccurate (my IP address changed recently and I am now a Canadian according to location services on my PCs with no GPS capabilities -- 200 miles off). It could be a circumstance of "that IP isn't known, but that block is owned by x ISP and here's a general location of where that is ... only the little dot happens to land on their house. It would be really smart for apps that track location for theft purposes to keep a reasonable history. If it's a mobile phone, the last known high-accuracy reading from the GPS should be presented along with lower accuracy results to help in situations like this. I'd imagine it wouldn't be terribly difficult to correlate several readings over a period of time and discard ones that are clearly not sane (as would have been the case with my phone in the archery place). A bonus would be to perform other actions when the device is marked "stolen", like take photos at certain intervals and upload them to the cloud to make it easier to "prove" your phone is in the hands of someone it shouldn't be (one of the tools I had did something like this).