You realize many of those exemptions were requested by the employees themselves?
Also waiting time is very abusable. Uber could just force quit your app if there aren't any rides, and then you have to try to login and it will boot you instantly every time. Then once there is a ride it accepts you. Exactly how to meassure waiting time is therefore not viable, either uber wont be able to boot you making their business model unviable or you will never get any wait time anyway.
It amazes me that in this hub of free enterprise and cheerleading for free markets, people act like companies will fall over the instant they hit a complication.
In EU, compulsory union membership is generally prohibited as violation of right-to-work and freedom of association.