Ann Cavoukian & K. Cameron, Wi-Fi Positioning Systems: Beware of Unintended Consequences (June 2011) (full-text).
This paper explores the identity and privacy issues that could arise from the unintended uses of the MAC address. Since the MAC address was designed to be persistent and unique over the lifetime of a Wi-Fi device, in a WPS, it identifies Wi-Fi devices that are closely associated with individuals — not only stationary routers, but personal laptops and mobile phones. When a unique identifier may be linked to an individual, it often falls under the definition of "personal information" through that data linkage and carries with it a host of regulatory responsibilities. The associated privacy issues range from lack of knowledge or consent of the mobile device owner for the use of the unique identifier, the possibility of unauthorized disclosure to third parties, or potential uses for secondary purposes.