Google and Apple lead industry specification to address unwanted tracking
security.googleblog.com
security.googleblog.com
Standard protocol built around Bluetooth-LE (with half the payload 36-byte payload available for vendor-data). Expose a non-masked public Bluetooth presence. Devices are supposed to track whether they are near the owner's home or other devices, "near-owner" mode vs "separated mode". Rotation policy of 15-minute address rotation when in "near-owner" state and 24 hours when in "separated" mode.
Physical requirements: minimum physical size for devices. Standards for movement detection (but not required to implement I think). Required noise-making, recommended haptic/buzzing and visual/light-making finding options. Serial number has to be printed on device.
A pairing registry maintained by vendors. Device serial numbers are tracked by vendors, with owner information stored there. Mandatory ability for non-owners to tell the device to play a sound when in separated mode. Disablement instructions. Mandatory ability for non-owners to push a button & have the device report a serial number. NFC says the supposed close proximity MAY be enough to get serial number without a button.