Earlier quoted context omitted.
Google should report a probability distribution for each truth claim.
While an interesting idea in theory... and I mean that!... in practice that's saying they just shouldn't provide answers. Even saying for the sake of argument that Google could assemble a meaningful and correct probability distribution, itself a rather bold statement, the average Google user won't know how to correctly interpret such a thing.
That said, this is a really interesting idea for behind-the-scenes work. The public might not want percentages, but I suspect experts could get some interesting results by diving into confidence levels and secondary answers.