A stumbler user's identity or location could be revealed by tracing routes from published GPS data or maps. In areas without much stumbler data coverage, you can see clear routes along highways and some residential streets.
Owners of Wi-Fi access points, including mobile phones with sharing Wi-Fi, may not want their unique BSSID/MAC address and location published. This is not exactly comparable to the Google Wi-Fi case in Germany. In addition to recording BSSID/MAC addresses, Google was (inadvertently?) logging Wi-Fi payload data that included cleartext user data.
btw, here's a zoomable map of the Mozilla Location Service's data coverage. Please help fill in the blanks! :)
About that map, a feature I would like is to fade spots which were scanned long time ago because WiFi access points might not last as long as cell towers. This way, as a contributor, I know in which areas to scan and, as a regular user, I know that the data for a specific area might be too old.
That's a good idea. The Stumbler app shows the coverage map (as blue clouds) on your mobile device, so you can see which individual streets are yet to be stumbled. Right now, our database is small and young enough that rescanning old data is not a high priority.
Well, Google's problem was that they chose an easily implemented solution - capture everything that looks even remotely like wifi and then physically ship the HDDs to Mt.View for analysis. It just so happens that the easy solution is sometimes blatantly illegal for incredibly obvious reasons.
Stumbler seems to anonymize the data on your device before sending it, which is the way it should be done. There is no reason to transmit any sort of wifi data except the AP's MAC address.
Owners of Wi-Fi access points, including mobile phones with sharing Wi-Fi, may not want their unique BSSID/MAC address and location published. This is not exactly comparable to the Google Wi-Fi case in Germany. In addition to recording BSSID/MAC addresses, Google was (inadvertently?) logging Wi-Fi payload data that included cleartext user data.
btw, here's a zoomable map of the Mozilla Location Service's data coverage. Please help fill in the blanks! :)
https://location.services.mozilla.com/map