Digital signs in Brookline are collecting data from your phone as you walk by

The linked article is about electronic signs installed by the Cambridge startup Soofa, which are collecting data from people’s phones to count the number of pedestrians who walk by, and then sharing that information with the town. The data collected is perfectly legal but may be problematic since IP information can be sensitive. According to the Soofa website, the sign encrypts the phone's Media Access Control (MAC) address to provide anonymity to the device, then stores the address and length of session time that the device spent connected with the sign.