It is an interesting question, for all of the non-Apple PC HW, laptops and server, the service is performed on-site under the supposedly watchful eyes of either the server admin or the owner of the laptop. I am assuming that it is the expectation that such a monitored repair is not a data risk. Give that HP is now headed down the encrypted file system route, that would be a next step in data security. Apple does seem to do on-site for servers, but not for laptops.
Ah, I see. That makes a little more sense... at least being watched by the sysadmin. I wouldn't trust the typical end user to watch and comprehend what was going on even if everyone in the company is supposedly knowledgeable.