I could easily see people doing this. Could really be scary if you think about it since you could easily gain access to passwords used for sites such as banks. Something to definately think about when sending a computer in for repair.
When working at a computer company myself I had co-workers who looked through images and we even encountered a few computers with child porn and reported the owners of the computer to the authorities. In that situation I guess it was good, but personally I don't think hunting through personal data or looking through pictures is right.
Another good reason to try to resolve the computer issues yourself I guess.