What if you used the location of a wireless device as part of authentication/authorization?
Location-based security for wireless apps (Nov 2002)
However for this to solve any problems, the location technology would have to be network-based not device based. You can't use device-based location (like GPS), because the problem is that you don't trust the device in the first place; you can't be sure that somebody isn't spoofing their location in the device's response. So passive (for the device) network-based solutions (triangulation, time difference of arrival, RF fingerprinting, …) are the only ones you can rely on because they are much harder to "spoof".