When you search for something on Yelp and you get 10 results, to places you've never been to before, and despite not visiting any of them beforehand, you choose one. That's what's happening here, and that's what's happening in Google search results. No difference.

... but that doesn't help informing another person's decision. Someone should track all of everyone's restaurant visits and quiz them in this style and publish the data for everyone's benefit

Sorry no lol, not the randomness aspect. What I mean is that Google has a very good guess of which restaurants I've been to, so rather than asking me to rate it 1-5 stars, I want it to ask "Is it better or worse than <Other Restaurant You've Been To>"? and then building ratings based on those results, with the option of me answering " I have not been there".

It just seems like better system than the current one, in which the Papa John's near my undergrad college and the best Italian place in my neighborhood are both rated 4.5 stars.