Unfortunately, it looks like said option is not coming anytime soon. The internet search giant is looking to deliver the option via software update in the coming months. In the mean time, the company says concerned Pixel 4 users can use the Lockdown feature. This makes your next unlocking require a pin, pattern or password.
What’s strange is that the Pixel 4 comes with a feature called Screen Attention. This prevents the phone’s screen from powering down when it detects that you’re looking at it. It’s odd that the same function is not used in Face Unlock, to detect that you’re looking at the phone before it unlocks. Despite everything, Google insists that the Pixel 4’s Face Unlock “meets the security requirements as a strong biometric” and “is resilient against invalid unlock attempts via other means”. The Google Pixel 4 and its XL variant is slated to be available starting 24 October. (Source: The Verge)
