I rarely use our garmin and only used it for that trip for kicks and grins to see elevations and ETA’s at way points. I seldom turn my cell phone on and have the gps turned off on it even though “they” can track it with cell tower pings when it is on. I have a ‘12 Ram and who knows what lurks under the dash and in the ECU?
This is one case were a tinfoil hat will actually work.
Just place it over the transmitting antenna...:^)