What you're suggesting can't work because there isn't cell reception everywhere, but of course that hasn't stopped car rental companies (I think) implementing exactly that with the predictable result of people being stranded in remote locations.
The real danger is that someone from Tesla is here reading your comment and putting it on the to do list.
What I'm really asking is if you are allowed to block the phone home process. Or, in superlative language that I suspect would resonate more with Tesla fans, "in the event of an apocalypse does your Tesla automatically brick itself or does it continue to function?"
If that happened, you would hear about it instantly. It's obviously not true.
I don’t know what particular conditions cause that. Maybe using phone as a key? And perhaps it was fixed. But it famously happened to Glenn Howerton.
This is different from Phone Keys that rely on Bluetooth or NFC and don't go over the network