Biometrics are an issue because in most jurisdictions (not just the US but globally), you can't be coerced to provide your password/passcode - but absolutely nothing stops LE from forcing you to provide biometric data to unlock the device.

Just tested it and can confirm it works. For those that don't have their phone handy or are worried about trying it:

• Just 5 presses is enough. You could do 6, or just spam the power button to make sure you've got at least 5 in. Any presses after the 5th don't do anything different
• when you do it, it opens up a menu with options to:
  • Power off
  • Make an emergency phone call to 911 (there is no option to select an emergency contact. It just calls 911 immediately)
  • Show emergency medical info
• Afterwards, you need to enter in your pin/passcode to unlock your phone. I have Face ID and the ability to unlock my phone via my Apple Watch. Both methods are disabled until I unlock my phone with my code.

Just to clarify and expand a bit: It’s 5 presses not 6, and you can do it in your pocket because it gives you a haptic feedback signal when it works, of a quick vibration in a unique pattern.

It depends on what your risk profile looks like. Sure, from a generalized risk standpoint punching in a number is vulnerable to physical snooping, but for folks who live in police states the greater risk is your information being accessed by people who physically have you in custody and can physically force you to use your biometrics to unlock a device.

turning the phone off also disables the biometrics if you turn it on again, it requires whatever lockout method you used previously

between the hotspots of fingerprints and shoulder surfing risk

If ICE is close enough to you to shoulder surf you, they are close enough to manhandle you, shove you and """assist""" you into touching your privates (aka biometrics).