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The Conditional Button

The mid-block crosswalk at a flashing-yellow pedestrian signal does work. A pedestrian presses the button, the overhead lights flash yellow, drivers slow or stop, and the pedestrian crosses. The system responds visibly, with no covert work happening underneath. The button does what it claims. But the same system also fails, often, in ways that have nothing to do with the button itself and everything to do with what is wired several layers behind it. A reader pointed out that drivers in his city tend to keep rolling through the flashing yellow if the pedestrian is still on the curb, and only stop once the pedestrian commits to the street. The same reader noted that drivers in his town do not give flashing yellow signals the obedience they give to red lights. Here in Jersey City the same mid-block button gets a more reliable yield because the lights are tied to traffic enforcement cameras, and drivers know that yield failures can become citations they actually have to pay. The button works because what is wired behind it works.

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The Dishonest Button

The mute button on the top of an Amazon Echo of a certain vintage is supposed to disconnect the microphone. A small icon of a crossed-out microphone sits next to the button, and pressing it turns on a red LED that confirms the disconnection. Software controls this button, which means the microphone remains electronically capable of capturing audio after the LED turns red, and the only thing preventing that capture is a line of code in the firmware. Security researchers have documented the capability and the manufacturers have acknowledged it. Whether the capability was ever exercised in practice is a separate question that the user pressing the button cannot answer from the front of the device. Bloomberg reported in April 2019 that Amazon employed thousands of workers worldwide whose job was to listen to Alexa recordings, and similar contractor review programs were acknowledged by Apple and Google for Siri and Assistant later that year. Subsequent Echo models added a hardware microphone disconnect that physically interrupts the microphone circuit when the mute button is pressed. Press the mute button on a smart speaker without that hardware disconnect and you are pressing the third kind of button in this series.

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