License plate scanners and public privacy

Here’s a story from last month about the Boston police and the use of license plate scanners. The scanners in question are just video cameras with some clever software designed to read plate numbers as they drive by. That may seem high tech now, but you’ll be doing it with your phone by Labor Day. Google recently demonstrated similar software that can read street address signs from Street View imagery.

So this Boston story is being presented as violation of privacy. Is it? What it really points to the slippery boundary between public and private these days. The technology required to build a plate scanner these days is not expensive. And it can’t be illegal to write down the license plate of a vehicle parked in a public place. What’s new is that you and your friends, just in the process of driving around with plate scanners, can assemble detailed information about the comings and goings of all your neighbors. The information is all public. I don’t see a way to stop it. This public-as-private pattern is showing up all over the place. The human form of the plate scanner problem is unsolicited face recognition. It’s not illegal for me to capture you in photo, and if the giant cloud brain is big enough to spot you in an incriminating position, that’s going to cause some discomfort.

This is already happening. The NameTag facial recognition app uses publicly available data to match your face with your name. This is what might be called a privacy invasion, only it’s powered by people’s natural desire to post labeled images of themselves on the web. The NameTag people are just aggregating that information. Did they sin?

One redeeming part of the story is that humans evolved in a world without privacy. We have no “biological expectation” of privacy. Google’s Vint Cerf went so far as to call privacy “an anomaly”. For almost the entire history of the human race, people have lived in small communities in which every action was accountable, every deed was scrutinized and judged by neighbors. We come from a small town, and to that small town we return. Welcome home.

2 thoughts on “License plate scanners and public privacy”

  1. Fascinating stuff…
    One point I’m not sure I agree with: “And it can’t be illegal to write down the license plate of a vehicle parked in a public place.”
    This is definitely true, but does it follow that it therefore can’t be illegal to “assemble detailed information about the comings and goings of all your neighbors”? Although, now that I think about it, internet firms like Facebook are basically doing the equivalent of writing down everyone’s license plate, and they do it with consent.

    The other issue I always think about in privacy law stuff is–who cares? It’s tough for me to identify concrete costs when people lose privacy or anonymity. You allude to this in your last paragraph. It’d be interesting if this privacy stuff is mostly a temporary concern, and people just end up adjusting over the next generation.

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