The missing element in ALL of these is...
Duress options! We should be able to unlock and use our widget with one finger/eye/PIN or combination of these. Another one - just alike but a different finger/eye etc - would provide a duress option, or several. If being mugged, the duress method unlocks the phone and calls for help, while perhaps experiencing "network problems". If enduring an illegal search at the border or stopped by a nosy cop, Duress One unlocks MOST of the phone but leaves certain other hidden elements encrypted or locked out. These let your attacker believe you're cooperating to avoid nasty consequences. Duress Two could be used to trigger a reset or brick the device. That's when you're already in bad trouble and trying to cover your butt.
The debate is stupidly limited to how to unlock a device, or keep it encrypted. We need other options than Submit or Refuse when faced with cops or criminal attackers.
This is also simple way to reduce ATM muggings as well. One PIN to access the account, plus a duress PIN to fake a transaction, call the police, and maybe even dispense marked bills. Strange that so many industry "experts" can't seem to think of this.
Biting the hand that feeds IT
