Quoting from google.com/privacy: "We restrict access to personal information to Google employees, contractors and agents who need to know that information in order to process it for us, and who are subject to strict contractual confidentiality obligations and may be disciplined or terminated if they fail to meet these obligations."

Speaking as a Googler, everything I've seen indicates a strong company-wide emphasis (both technological and process/policy) on user privacy. Not only who CAN access your individual data, but who DID access it and why.