And issues of privacy/security immediately arise ... such as "authorities" just having to aim your own device at you to unlock/access it without a warrant.
It just gets better and better.
Once again, Luddites rejoice in the misfortune of the burdened.
I have read that if the Power/Wake button is pushed 5 time in succession that a passcode becomes mandatory to unlock the phone. Just anticipate the authorities grabbing your phone and start pushing the button!
Also, if as stated above, 30,000 facial points are mapped, just how identical are identical twins? Perhaps to the human eye they appear the same, but are they truly?