[sgtmas2006]

Do we know this?

It is not possible truly to know one way or another at a complete level, although it is unlikely. Saying they are not this powerful is, well, simply not true. It is not possible without creating a huge skunk-works internal project binding people to secrecy.

Google doesn't have the power to bind people to secrecy in the same way that say, the CIA, FBI, or NSA do. It does not mean that they do not have the capability of doing these things.