I haven't.

It's part of discussions around hypothetical futures where everything is self-driving and the vehicles communicate with each other to form dense convoys on places like freeways where there aren't pedestrians.

I certainly haven't heard any mainstream suggestions that self-driving taxis ought to drive faster than humans in spaces they share with human drivers and human pedestrians.

> I've seen plenty of robotaxi huckers advocate for speed limits 'appropriate for robot response times'

Where?

I think maybe robotaxis should have speed limits appropriate for driving into trees and fire trucks.

A company that systematically speeds is a nice fat piggybank for governments wanting a little extra money in their budget or a political win. These vehicles are logging their current locations and speeds constantly against a map of known speed limits. It's much easier for a government to request those records and assess a fine than go after individual motorists with politically unpopular measures like speed traps and traffic cameras.

> that will include as much speeding as risk/reward dictates

Speeding can usually be brushed off as carelessness. Where it can’t, we charge it more harshly.

A robot programmed to speed serves a jury mens rea on a plate.