I don't know what details I would be allowed to share, so I'd better not share any. You can try looking it up on the Internet.

But Google does a lot of work to protect against insider threats, because everyone understands that in an organization of this size there will always be bad apples, spies, etc. Google's systems are designed to protect customer data from malicious employees using technical measures; it's much more than just "if we catch you, you're fired" as was asserted upthread.