Starting on Black Friday (11/25) and running through New Year’s Day, two U.S. malls — Promenade Temecula in southern California and Short Pump Town Center in Richmond, Va. — will track guests’ movements by monitoring the signals from their cell phones.

The tracking system, called FootPath Technology, works through a series of antennas positioned throughout the shopping center that anonymously capture the unique identification number assigned to each phone (similar to a computer’s IP address), and tracks its movement throughout the stores.