There are plenty of other industries - CCTV monitoring, pool lifeguards, pilots using autopilot, airport x-ray operators - and they all know it's incredibly har

There are plenty of other industries - CCTV monitoring, pool lifeguards, pilots using autopilot, airport x-ray operators - and they all know it's incredibly hard for humans to remain vigilant for hours on end when there's no action. I think it's pretty well known in the self-driving car industry that safety drivers do a great job if they have to intervene several times an hour. And they're good at getting the vehicle unstuck if there's e.g. a flat tyre. But for a system that only needs an intervention once a week? The safety drivers often won't react fast enough - they're just there to take the blame.