The characterization of the adversary here being some malicious third party, though traditional, is something of a bogeyman as far as actual risk is concerned. Institutions running large mesh networks are in a privileged position to track users in this way.

At Brown University, complete connection logs for each wireless access point have been kept for no less than two years. A group of students last year were given this data and produced a (historical) map of student movement. There is no reason to believe that the University could not or is not rendering such a map in real-time.