One of the chief problems with “luxury surveillance” devices, like smart glasses with baked-in video recording cameras, is that they often look indistinguishable from regular eyewear, meaning you might be recorded without knowing it. But now there is an app that can detect and alert you when someone nearby is wearing smart glasses, or potentially other always-recording tech. The Android app, aptly named Nearby Glasses , constantly scans for nearby signals that emit from Bluetooth-enabled tech,