The quality of South African reporting is not particularly great, but it seems like Uber allowed two major lapses to occur, allowing a criminal rapist to drive for them, and then allowing the same person using a "stolen" Uber vehicle to pick up passengers. No comment from Uber in the article, but this is pretty shocking.
It's also interesting that the first attack was initially reported as a "false Uber taxi", but it turns out it was the real thing: http://citizen.co.za/1206095/uber-condems-kidnapping-rape-in...
And another two alleged cases in another part of Johannesburg: http://www.heraldlive.co.za/news/2016/09/08/obstacle-course-...