TfL is going to track all London Underground users using Wi-Fi Want to opt out? Turn your Wi-Fi off May 22, 2019 https://www.wired.co.uk/article/london-underground-wifi-tracking
TfL launches wireless device tracking to gather Tube data July 8, 2019 https://www.computerweekly.com/news...-wireless-device-tracking-to-gather-Tube-data TfL: Wi-Fi data collection