researchers found that "the overwhelming majority of
Android devices are not implementing the available
randomization capabilities built into the Android OS,"
which makes such Android devices trivial to track.
[...]
Apple, meanwhile, introduced MAC address randomization in
iOS 8, only to break it in iOS 10. [...] its network probe
broadcasts to include a distinct Information Element (IE),
data added to Wi-Fi management frames to extend the Wi-Fi
protocol.