I've thought about the idea of a "lock the thief inside" kind of alarm system, but you're right. How do you stop them jumping out?

I've also thought of this.

1. Lock doors, secure windows.

2. 100% throttle

3. after 15 seconds, 100% steer left

Of course, there are certain... moral issues... surrounding this idea which have prevented it leaving the notes on a napkin stage.

100% throttle for 15 seconds means my car has gone through my garage door into my garage.

If another car isn't there to stop it, the car has now gone through my kitchen or my daughter's bedroom.

100% throttle for 15 seconds on a multi-level parking garage means my car has now plunged N stories, or gone for a swim into the pond/river/drainage ditch behind the parking garage.

Don't be judge, jury, and executioner.

Or in less cliche terms: separate the asset recovery function (where you can help without moral issue) from the law enforcement function (where you cannot help without creating moral and privacy issues).

Just immobilize the car: the car's owner, leasing/financing company, insurance company, and police department will all be happy with just that.

Person breaks into your car to escape violent gunman (let’s assume we’re in America), your car summarily executes them.

Alternatively: person is stealing your car, you have decided that theft deserves the death penalty, you execute them with your car.

Someone steals your car, your car accelerates and turns hard left, killing the occupants of other cars around them.

Seriously, I don’t get people who are so hell bent on trying to come up with ways to execute people for committing crimes.

yes.

So I could execute you if your high speed left turn injured me?

Or have the car rendezvous with the nearest police car which wouldn't probably leave the thief time enough to exit.

Even if he successfully gets away how likely is he then to steal another Tesla?

Even if a hacker sells them a zero day hack then it will only last a single day before Tesla updates its entire fleet.

Couldn’t that be thwarted by thieves using car covers that were designed and made to act like Faraday cages? Like those bags they sell for cellphones?

This would prevent automatic updates to the software and remote control at the same time.

They could do that, or they could use a 30 year old flatbed tow truck bought at auction for $800

Hell, if you can afford it, just buy a tow truck, the police would probably help you. (I recall a study from many years ago, where people would functionally help a car thief because of how annoying car alarms were)

imagine a kid locked in a toasty car for a whole day before the update gets deployed

It would be the other way around. You wouldn't be able to electronically break in using the zero day after the update.

Then you do the same thing as you would in an unconnected car, break a window.

Technically, you don't need windows in an autonomous car, and even on a normal car you could have the views captured by the external cameras projected onto the windshield and windows. all made of solid steel ...

That's where I want to be when my autonomous car crashes or collides. Inside a crumpled steel coffin.