> And then how do I loan it to a friend without the rigamarole of adding them as an authenticated user?
By making adding an authenticated driver not a rigamarole, but easy and intuitive.
> What if I'm not able to add them as an authenticated user or authentic myself to let them drive, e.g. I'm injured or very drunk?
They call you an ambulance.
In the future?
They call 911, and they read the license plate number and the authorities send an override signal that turns on the car and only allows it to be driven to the nearest hospital that appears on the screen on the console. If they go off course, they have 30 seconds to get back on course before it coasts into a 5mph limp mode (to find a safe place to pull over) for 1 minute before it completely stops and shutsdown and locks them inside for the police to come get them.
Eh, the car will probably be self-driving at that point, so probably only the first half.
The last thing I want to see on any car is the ability for the government to just remotely hijack random cars. Not just because cops already and routinely abuse their privileges (imagine some crazy police officer doing that to their ex girlfriend!), but also because any such capability can and eventually will be abused by malicious actors. Think of the usual "for the lulz" trolls, organized crime rings involved in looting people, or nation-state enemies.
> By making adding an authenticated driver not a rigamarole, but easy and intuitive.
We'll have to agree to disagree. I don't believe that this will be possible in many situations. What if I'm not near my car? What if my phone is dead? What if my car's battery is dead and it needs jumped?
I'm also just cynical that the automakers or app developers are able to not enshittify the process.
What if when I set my wife up I added her as a user but not admin and now she can't share with someone without having to involve me, which may not be physically possible in all circumstances.
> They call you an ambulance.
You don't call an ambulance to take a drunk person home. Calling a taxi when there is someone able to drive is a waste of money and a huge inconvenience the next day to retrieve the car.
You also can't call an ambulance in the wilderness.
I also meant injured in a more broad sense. What if I just have a bad headache or migraine? I don't want to be fumbling with my phone or car electronics trying to navigate adding someone.