I don't think that moving servers is at all realistic option for google. I am much more worried about traffic logging at the isp than I am of what google records. However I will concede that because of the shear volume of data that google collects and retains it is a much is a worrying if they decide that it is ok for them to go dredging.

Or disclose in a big blinking disclaimer, here is what we track and here is who we are required to give it to. With full disclaimer that is readable and not legalese, I feel that it is fully ethical to provide said information to the US or Chinese government or whoever.