Here's the thing.... Our military/government uses cell phones to create an ad hoc network, which is dome via the same device in your phone that uses the IMEI number for tracking purposes. They can actually listen to your surroundings even when you have it turned off, even when your battery is removed. they use this tehnology in Iraq to remove HVT's (High Value targets), and they can actually send airstrikes to the location of that phone/mobile device. So, there is already a registry of all the IMEI numbers in the world, and if a phone is stolen it can be tracked much easier than most people think. Triangulation is not necessary, unless you are working off of a timestamp. also, with this ad hoc network, it is possible to access cell phone services for free; and, since there is no actual law against it and the phone comes with that technology, it is possible and legal to access that network. Additionally, it is possible to disable the IMEI tracking device in your phone, but that takes a pretty high amount of circuitry knowledge and most phones are designed so that the part of the circuit that includes the tracking device is necessary for any other phone functions.