I've just moved home (same town, another neighborhood) and took my 3 Wifi Access Points to the new home. I use the same old SSIDs.
Google Geolocation API sees those SSIDs with those MAC Addresses and thinks that I'm at the old apartment.
Everything that relies on that API without checking GPS thinks I'm there. Like Chrome on Windows with websites that use the HTML5 Geolocation API. Even Android Device Manager thinks my devices are at the old location because of the Wifi Networks.
If I turn off my Access Points it knows the right location because of the other networks around here.
It may happen with other Geolocation APIs that uses the MAC Addresses of the Wifi Networks. But I think Google's is the most popular one, right?