There's a few problems with this, people regularly hand their phones to people who aren't themselves and if the phone disables itself every time this happens, I

There's a few problems with this, people regularly hand their phones to people who aren't themselves and if the phone disables itself every time this happens, I don't think this technology would ever catch on. The solution to avoid this is that you'd have to report the phone stolen... at which point the phone company can just ask you for your IMEI, which is a 15 digit code (usually hidden under your battery, or enter *#06#) you're supposed to write down in your handset manual. With this code and a report that your phone is stolen, the phone company will ban the IMEI number and the phone is useless (unless the person wants to spend $50 getting your handset unlocked and then $10 to get a new sim card and then $10 to put time on a stolen phone, which when you're stealing phones, I doubt you'd go to that trouble). On CDMA phones it's your MEID number, which if reported will ban the device, but as CDMA's are tied to one network it means the phone is permanently useless. So honestly, I don't see how this technology is useful in protecting a cell phone from being stolen. My wife's taken my cell for days, I don't really want my phone getting locked because of it, and when I was younger (before I got a cell) my parents always handed me one of theirs if I was going to be out late, which I'm sure many parents still do today. And if you need to report the cell stolen, then it's pointless because there's already well established systems for getting cell phones banned from a network.