Most Wi-Fi networks transmit a periodic station ID – such as “Home WiFi” or whatever you call your AP.
Many devices, including smart phones, can collect AP names and locations as they are moved about. Services like Google use this to provide enhanced location-based services.
Go to Wigle.net to see a map of Wi-Fi AP locations, globally (This is not based on Google’s system).
If you use your phone as a Wi-Fi hotspot, that too can be intercepted by other nearby devices that forward the ID and location into global databases.
There are two ways to reduce this collection of your Wi-Fi data and location.
- Don’t use WiFi! Use wired Ethernet connections instead. You can also connect your phone via a USB-C to a computer that supports USB network connections. Or you can use a USB-C to Ethernet dongle – and avoid activating Wi-Fi.
- According to this news report at CNet, you can append _nomap to the end of your SSID and this should flag systems to not collect data on your AP. Google proposed use of the “_nomap” option as a way to comply with European privacy regulators.