Gripping buttons on both sides of iPhone X disables Face ID, recognition works with most sunglasses (AppleInsider)

I'm guessing Apple's patent-pending portfolio in this context is extensive...

"Keith Krimbel emailed Federighi this week, and received a response which he share on Twitter. Krimbel asked what measures Apple was taking to ensure a thief cannot take a user's iPhone X, point it at their face and then run away with the device unlocked.

"There are two mitigations: if you don't stare at the phone, it won't unlock," Federighi said. "Also, if you grip the buttons on both sides of the phone when you hand it over, it will temporarily disable Face ID."

Krimbel also asked if Face ID will work with sunglasses, and Federighi explained that "most" but not all will not interfere with the biometric unlock mechanism.

"Most sunglasses let through enough IR light that Face ID can see your eyes even when the glasses appear to be opaque," he explained. "It's really amazing!""

Gripping buttons on both sides of iPhone X disables Face ID, recognition works with most sunglasses