And here is a link to Federighi's response to MacRumors query about face recognition and sunglasses. It appears that by every measure Apple's biometric facial recognition is over 3,000 times more discriminating than fingerprint recognition. That does not mean it cannot be broken but it is a LOT harder to break than the predecessor fingerprint recognition.
"All you've got to do is own up to your ignorance honestly, and you'll find people who are eager to fill your head with information" --Walt Disney
