With robotaxis that are owned by other people who don't need the vehicle at that time, which is key to massively increasing utilization of the fleet, this does bring up interesting situations/wrinkles
For example, you will likely need to set hours of operation and buffer times and people using the service will need to pre-enter routes or commit to only using the vehicle for a certain period. Otherwise lets say you work 9-5, you get to work and set your robotaxi out to do its thing, what if someone hails it at 3pm and takes it on a 4hr milk run? That won't work, the vehicle needs to be there at 5pm to drive you home or you're hailing your own robotaxi.
THe same could be said for your robotaxi operating at night, it needs to be back at your house in the morning at a certain time. What if someone refuses to get out, does the car drive itself and an angry passenger back to your house? Does the seat need an ejection mechanism?
All kinds of interesting stuff when you really dig into how it would work