(a) There will be more than one of these dispatching services, so you'll just hop.
(b) There's an inherent TOCTTOU problem, since they're only checking licenses when you sign up, not every time you pick up a fare. You'll just "rent" someone else's license; there are presumably tens of thousands of people who don't care what their cab dispatch reputation is.
Being able to switch services or rent someone else's credentials are different problems than being able to cheaply create a new positive profile on a given service. Switching doesn't help you much if there's one dominant dispatch service that everyone uses, and renting someone else's credentials drives up the price of scamming the system.
This is kind of a silly argument, though, because my main point was actually agreement that a taxi review system would probably be horribly broken. I just don't think it would necessarily be broken in the exact same way that eBay's is.
There are probably not tens of thousands of people with the correct license endorsement. Those who do have a commercial driver endorsement are probably not so keen to rent it out.
(a) There will be more than one of these dispatching services, so you'll just hop.
(b) There's an inherent TOCTTOU problem, since they're only checking licenses when you sign up, not every time you pick up a fare. You'll just "rent" someone else's license; there are presumably tens of thousands of people who don't care what their cab dispatch reputation is.