Let's say a request is made for Google give over loads of Gmail passwords. Could they not silently implement an extremely strong password encryption on the affected accounts, and hand over these passwords, knowing that the feds wouldn't be able to crack them without a significant amount of time.
Also, are the feds likely to check to see if these passwords are legitimate? If my password was 12345 and Google simply told them that my password was 54321 then how could the feds possibly know that the passwords sent over are real?
EDIT: Obviously, I know this is highly illegal, and would land any company in trouble. I'm just wondering whether, theoretically, this is possible for a firm to do to circumvent any action from the feds.