It was computer scientists who made the car vulnerable in the first place

A luxury vehicle today contains multiple computers. During an hour's drive, it thus produces multiple gigabytes of data. Even less expensive vehicles are now brimming with information technology. The growing interconnection of the individual components opens dangerous security holes. One of these has now been closed by computer scientists -- with the help of software that manufacturers can retrofit into any car.

Or, just drive a 1974 Plymouth, cars worked fine then before boneheads in Silicon Valley.

Here is a clue.  Robots know how to drive, no connectivity needed.  So, when the key is on, then the internet connection is mechanically disconnected.  The concept is called the on/off switch.

But, I will notice they did a great verification protocol, and we should be looking at that.  Smart Card uses something similar.