Originally Posted by Cymro

While it may well be that some Über drivers outside the UK are moonlighting, I've never been in an Über car that didn't have the private hire sticker on it - so the cars and drivers are themselves licensed private hire operators. (I believe that is also the policy).

So unless there is a suggestion that private hire operators are routinely un(der)insured there's no reason to believe that it's any more risky, in insurance terms, than taking a black cab.