Probably a violation of the CFAA. Lots of people hate it because they think it's overreaching, and lots of companies use it to legally threaten scrapers and security research. But in this case Google is doing mass unauthorized use of other people's computers.
If I'm doing price comparison between online vendors, I will---as a human---put some items in the cart and get right to the edge of checkout to determine what my final bill would be. I may not close the sale if I'm looking at a better option elsewhere.
How is what I'm doing materially different from what Google's doing? Is scale a factor that matters for CFAA?
I think FTC should install a law that says that shops should be more transparent about their prices. That would solve the entire problem in the first place.
