You can fairly easily get the current location for a mobile, at least down to a specific country and state.
Basically you pretend that your sending an SMS to the device and the home network will return you some data which includes the serving network, from this data you can guess location fairly accurately.
It’s a little dodgy, some networks will put filtering in place to stop this, but not many bother.
If you want to see it in action here’s somewhere selling the service masked through a basic JSON API - https://www.messagebird.com/en/lookup
