The basis of social interactions might change, too, from a set of commitments founded on trust to calculations of risk and reward derived from the information a computer attaches to someone's face.
Relationships might become more rational, but also more transactional.
In democracies, at least, legislation can help alter the balance of good and bad outcomes.
European regulators have embedded a set of principles in forthcoming data-protection regulation, decreeing that biometric information, which would include “faceprints”, belongs to its owner and that its use requires consent—so that, in Europe, unlike America, Facebook could not just sell ads to those car-showroom visitors.
Laws against discrimination can be applied to an employer screening candidates' images.
Suppliers of commercial face-recognition systems might submit to audits, to demonstrate that their systems are not propagating bias unintentionally.
Firms that use such technologies should be held accountable.
Such rules cannot alter the direction of travel, however.
Cameras will only become more common with the spread of wearable devices.
Efforts to bamboozle facial-recognition systems, from sunglasses to make-up, are already being overtaken; research from the University of Cambridge shows that artificial intelligence can reconstruct the facial structures of people in disguise.
Google has explicitly turned its back on matching faces to identities, for fear of its misuse by undemocratic regimes.
Other tech firms seem less picky.
Amazon and Microsoft are both using their cloud services to offer face recognition; it is central to Facebook's plans.
Governments will not want to forgo its benefits.
Change is coming.
Face up to it.