Does the controlling app connect the cell phone directly to the car, or does it rely on the cell tower infrastructure?
There was a story a year or so ago about some guy with a cell-phone-controlled car who drove out into the Nevada desert, “zero bars”, got out of his car, somehow locked it, and couldn’t unlock it because there was no cell phone coverage there.
Don’t know how he got out of there ... couldn’t call Uber either without a cell phone.
Hitchhike?
I spend a lot of time in areas with no cell phone coverage in Nevada. Three or four times a year now I run across idiots that are lost. They are depending on cell phone tower gps and don’t have a clue what to do when they get out of range. It is laughably funny to find lost “Burners” in August. They invariably are stuck because their Subaru Outback is high centered on a rock or their Barbie Jeep is stuck in powdered alkali. Their defense is the road looked ok on my phone.