But what about the dystopian flip side? You commit a crime once and suddenly you aren’t allowed to travel, otherwise the other passengers would feel unsafe? Or your transportation costs increase by 5x to account for you needing private-only accommodation?

Sounds like a great way to isolate someone and make sure there is no chance of rehabilitation, being shunned by the car swarm and isolated away

totally, I think the social credit score system in China, background checks for employment, no-fly lists are all things we should look at when building such systems. Ultimately though it's not going to be fair, I don't really care for subway performance arts as practiced in urban metro systems and I'd vote to eject and ban the artists, whereas someone else might find that to be an authoritarian overreach

but how would the driverless vehicle know that something went down? reports from other passengers? What if the other passengers are lying? Or simply don't like you? So the vehicle will have to surveil the passenger conversations and actions and beam it up to Waymo or Cruise (ok, that's fine, a human driver would do that too). But who will look at the surveillance? An algorithm? And, what if they say you are smelly? The microphone and camera won't pick that up...

And the smelly (or messy) passenger problem doesn't even require ridesharing! Who will clean the previous passenger's McNugget crumbs off your seat?

all of these are pre-existing problems with public transport that have solutions along the anarchy<->totalitarianism spectrum, with US, European and Asian mega-cities' transit agencies serving as illustrative examples of tradeoffs of various approaches. I'm not sure how self-driving changes the game, ain't nobody helping you when the foil and torch lighter comes out on BART late at night.

Well typically you're not the only other one the train (at the very least there's an operator). Somehow sitting in a small car next to someone else feels different.