[defo_nonconvex]

Possible on Android and without root?

[distances]

For avoiding wifi tracking I suggest Smarter Wifi Manager [0]. It's great for automatically keeping wifi off when not at home/work.

[0] https://play.google.com/store/apps/details?id=net.kismetwire...

[TACIXAT]

As of iOS 8 and Android 5.0 the operating systems should do it automatically.

[michaelt]

  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.

https://www.theregister.co.uk/2017/03/10/mac_address_randomi...