I can picture a situation, which I don't think would be very unrealistic. What if someone comes into possession of my iPhone X without my knowledge, and then unlocks it with Face ID using my face all the while I am not aware of anything that happens? This would not happen with Touch ID because normally you would not touch (what you think is) someone else's phone, and even if you happen to touch your phone thinking it belongs to someone else (because the thief fools you into thinking it is not yours), the moment it unlocks, you'd realize it's yours. But with Face ID, the act necessary for unlocking (looking at the iPhone X) can be much less of a conscious act compared to what is necessary for Touch ID (touching the fingerprint sensor of the phone), so I'd think it would be much easier for a thief to unlock a Face ID phone without your knowledge than with a Touch ID phone. For example, I may inadvertently leave my iPhone X on my desk at work to go to water cooler, a co-worker picks it up, and waves it in front of me. I don't know that she is holding my iPhone X, but I just unlocked my iPhone X for her, unaware. Or what if a pickpocket pulls my iPhone X from my pocket without my knowledge, then stands next to me and unlocks it using my face when I glance at my iPhone X that the pickpocket is holding, thinking it belongs to the pickpocket? Did I miss something from the presentation or any press releases or FAQs, or is this a legitimate concern?