Welcome to the United States where you find out the pricing for a medical service 6 months after receiving the service, then keep finding out about it for another year, random bill upon random bill.
Sad thing is, some people even get billed twice for the same service too and might not even be paying attention fully to notice either. Someone I know almost mistakenly paid twice because of a double billing error. Then I seen on a TV commercial, some college has an entire degree on medical coding and billing... Not sure why tech isn't being used to help, seems insane you have to go to college just to learn how to bill people properly and then probably still end up making mistakes.
Presumably the rate chart of the cab is known. It's not a random number that springs on you months after the ride with no real logic other than 'this is how it be'.
Except the driver has discretion to choose a path and it’s easy to take a longer route when the passenger is not a local. Likewise it’s easy for hospitals in the US to pad their charges arbitrarily (e.g. $50 for a Tylenol/Panadol tablet, a genuine example)
