Not a hypothetical guess. Carriers have access to location data from multiple sources and have been selling it. Some of those sources are combined with GPS in

Not a hypothetical guess. Carriers have access to location data from multiple sources and have been selling it. Some of those sources are combined with GPS in this particular case. Also you asked if carriers need a backdoor, which I answered: "Wouldn't that need a backdoor in the OS's GPS software/driver?" PS asking a question and berating any answer you don't like is not exactly optimal strategy for getting people to answer your future questions.