Nobody knows, as far as I can tell; I haven't found any actual sources and I don't think the code is present in a public release anywhere for anyone to look at. I'm assuming it must work off of MAC at a minimum, since most offices have the same SSID across buildings. It doesn't really seem "designed" as a spyware/audit feature, since it would be a terrible flimsy one, but it also just doesn't seem that useful compared to the "yuck" factor it generates and the potential for abuse by crappy employers/managers.