Apple says the probability that a random person in the population could look at someone else’s iPhone X and unlock it using Face ID is approximately 1 in 1,000,000, compared to 1 in 50,000 for Touch ID, but it notes the probability of a false match is different for twins and siblings who look like you.
We’ve already seen that Face ID can be fooled by identical twins, and now a video shared on Reddit appears to confirm that Face ID can sometimes fail to distinguish between siblings who aren’t twins but have similar appearances.
Apple is very transparent that Face ID can be less reliable in these situations, so the video doesn’t come across as a PR disaster in the making for the company. But, it does suggest that Face ID isn’t 100 percent failproof.
For those concerned about the security of their iPhone X in these cases, Apple’s only recommendation is to use a traditional passcode instead of Face ID for authentication. Unfortunately, at least for the time being, that means disabling one of the key new features of a smartphone that costs at least $1,000.
We’ve reached out to Apple for comment, and we’ll update this article if we hear back.