You know how your iPhone would lock up after failing to authenticate someone else's fingerprints a few times? Apple examined the demo device's logs and found that the same thing happened to it. "People were handling the device for stage demo ahead of time, and didn't realize Face ID was trying to authenticate their face," a company rep explained. "After failing a number of times, because they weren't Craig, the iPhone did what it was designed to do, which was to require his passcode."

While it's great that the feature is working exactly as intended, it shows why facial authentication might not be ideal for everyone. If you frequently let family members or friends use your phone, will your iPhone X lock up all the time? In that case, it might be better to switch it off completely -- or get another phone altogether.