Google does not openly advertise the fact that they have different location data for different users. However there is good anecdotal evidence an hearsay that Google Maps API returning inaccurate results may be by design.
The evidence is most prevalent in the geocoding of locations. The latitude and longitude Google assigns to different addresses is not “set in stone”. It is an interesting anomaly given the fact that places on earth should not move with regard to their latitude & longitude outside of plate tectonics.
The team at Store Locator Plus® has long held a theory that Google intentionally subverts accurate location data; quite likely to gain competitive advantage for their own products and services.