>This is wishful thinking and clearly false
No it's not, but you'll likely never see it that way let alone admit you're wrong on the internet.
>If it were true, there wouldn't be any at-fault crashes.
Computers follow rules perfectly 100% of the time yet we still have software bugs.
>The only accurate claim you can make is "human traffic sometimes follows rules, and the rules that it sometimes follows change regularly from person to person and moment to moment".
You understand rules to be flexible and subject to some interpretation (like laws, not like a firewall config). Context is important. The rules that govern human interaction are complex.
>That's not a defensible state
This comment proves otherwise.
>Implicit in your mistaken description is a pretense that humans are psychic and that we can predict what other people will do, but we aren't and, despite believing otherwise, we can't
Humans don't need to be psychics to accurately predict what other drives will do. Humans are really good at pattern identification and picking up on subtle cues.
>That's why defensive driving is so important.
Being able to make accurate predictions of the future state of what is around you based on the current and past state of what is around you is far more helpful than defensiveness for any amount of defensiveness.
The behavior by AI vehicles fielded by Cruise and similar is a glaring example of that while defensiveness is great at avoiding liability it does not necessarily make the road around you safer (maybe even worse, as many comments anecdotally point out). This is the main gripe people have with AI and human driven vehicles that practice defensive driving to the point of absurdity. Defensive driving without human level ability to predict what other traffic will do is not sufficient for the kinds of situations that are regularly encountered in urban areas.
Most people will never get in a car crash in their entire lives (bumping into an object in a parking lot notwithstanding). I think that speaks for itself.