Edit to add: a better metric would be something like "billions of decisions made where human life was at stake".
Makes sense doesn't it?
Well, actually no. The Google cars drive the same route every day in Mountain View with no deviation, so those millions of miles are really the same 10 miles over and over. Even seen 3 in a row behind each other.
Fools the regulators, and apparently you, though.
I don't think its possible to fool the regulators, but even if it was possible there are dramatic consequences for lying. Volkswagon tricked regulators into thinking their car didn't emit as much as it really did in 2007-2015, and ended up having to pay 33.3 billion dollars in fines and returns[2]. Volkswagon stock went from a high of around 27 to 12. 5 years later, it's only recovered to around 16. The massive lawsuit that would be formed if Tesla's (or other automated car maker) car was found to be unsafe would likely be even larger. Furthermore, it would crush the self-driving car business semi-permanently. VW at least still gets to make environmentally safe cars, Tesla and Waymo's main value proposition is dead in the water.
Basically, even though there are incentives to lie and cheat, I think the incentives to try to make something that is safe is far, far greater. And while I'm sure there are Google cars driving the same route every day, I'm sure there are also tests being done in all sorts of conditions all over the planet. I think that practically, socially, and politically speaking, we can use billions of miles driven. The stakes are way too high to lie.
[1] https://en.wikipedia.org/wiki/List_of_self-driving_car_fatal... [2] https://en.wikipedia.org/wiki/Volkswagen_emissions_scandal