What's so terribly bad about having a driver who once downloaded some kidyporn? Uber has a rule that they won't carry unaccompanied people under the age of 18, so I doubt many kids are hailing Uber cabs as they will get rejected 99 times out of 100. Not that liking underage porn means that the person is all that likely to do anything bad in real life. People who like horror films are unlikely to pose a risk of suddenly going on a rampage with a chain saw.