A new app called Nearby Glasses uses Bluetooth signals to warn people when smart glasses may be close. Its existence reveals a social problem that the eyewear industry has not solved: a camera can now look almost identical to an ordinary pair of glasses. The person being observed may have no reliable way to know whether a lens is recording, processing faces, or simply idle. Detection therefore becomes another consumer service, running in the background to restore a fragment of the awareness that discreet hardware removed.

The arrangement is strangely circular. One connected device is required to disclose the possible presence of another, and neither can provide complete certainty. Bluetooth can be disabled, identifiers can change, and an alert cannot explain the intent of the wearer. Yet the app matters because it expresses a demand for reciprocal visibility. Smart glasses give their owner information about the surrounding world; people in that world want information about the glasses in return. Without shared conventions, public space becomes a contest between sensors and sensor detectors, while consent is reduced to a notification that may arrive after the encounter has already begun.