I was actually just listening to a podcast this week about the Uber strike in Africa. Apparently Riders/Drivers are protesting Uber by scheduling rides and then, when the Driver shows up, cancelling the ride and paying the Driver directly when he shows up (they refer to this as "going karura").
Uber commented on the story noting that frequent ride cancellations flags an account for a fraud investigation.
I asked Uber if I could talk to a company rep in Kenya about going karura. A spokesperson for all of sub-Saharan Africa wrote back, saying, in part, "Repeat canceling by either a driver or rider could be flagged by our fraud technology, which will then result in an investigation."
From This American Life, Made to Be Broken
I imagine that fraud trigger extends beyond Africa so just be careful if attempting to game the credit in this way.