I think the point is more about what people do when others aren't watching. Uber and Lyft have drivers. Public transit has other passengers, staff, and is gener

I think the point is more about what people do when others aren't watching. Uber and Lyft have drivers. Public transit has other passengers, staff, and is generally constructed in a way to be more resistant to malfeasance (and amenable to cleaning) than your average car. Self-driving cars will not have that, so you need to counter it somehow. Cameras and fines are probably sufficient, but OP's point that probably charging people more upfront will reduce this is probably valid, as the type of person who is willing to pay more is also going to be easier to collect fines from.