Wouldn't people rather be in their own semi self-driving car, where they are not recorded and can go anywhere they want(including very long distances or bumpy terrains), plus they could take control of the car anytime they wanted? That would be a more reasonable option for many, not a taxi that you have no control over and where you're recorded like a rat in a laboratory.
2008, "All licensed cabs in Windsor will have on-board cameras by the end of August" - http://www.canada.com/windsorstar/news/story.html?id=1ea2956...
2000, for NYC "The in-vehicle security camera system takes digital photo images of the entire passenger area of the vehicle, and consists of a small camera with integrated infrared lighting that is installed above the vehicle’s rear-view mirror." - http://www.taxi-library.org/tlc-cameras.htm
2015 Uber driver with dash cam - http://www.latimes.com/local/lanow/la-me-ln-uber-rider-arres...
Also it's easy to put a webcam inside an SDT to monitor what's going on - it's not a problem with a human-driven taxi that he could see you, so it shouldn't be seen as a violation of privacy. If you do something nasty a machine vision system can detect it, lock the car down, and drive you to that aforementioned police station.