I find it interesting that iPhone doesn't do a sanity check of these WiFi/cell fingerprinting based results against the GPS receiver it actually has. I can understand how WiFi only device would not have such an option, but why not do it on iPhones if Apple is known to be against location spoofing?
It does fall back to the GPS receiver if no internet and no cache but I suppose it's just more power efficient and not on anyone's minds that people would MITM for this purpose.