From what I know about Google, they are serious about least privilege type of stuff internally and employees dont get arbitrary unbound access to systems or data.
IIRC there was some basic safeguards though, like a query must have had like 10 unique occurrences or something. I also have no idea if you could tie searches to people.
I was just looking at aggregate numbers. That was really cool. It was like Google Trends but with real numbers!