Google knows where your AP lives, and it's not that hard to query it! Geolocation API Network Protocol can work based on a query with one AP mac address. Testing it with a random access-point near work gives me: http://samy.pl/mapxss/?mac=00%3A1A%3A1E%3A15%3A90%3AE2. Found via Hacker pilfers browser GPS location via router attack - The Register where the user is not asked for permission to trace the location when a wireless router is used. And indeed: 'Scary how accurate it is'.
Google knows where your AP lives, and it's not that hard to query it!