Privicy is not just hiding porn
There are many things which whilst legitimate you would want to hide from a technitian, even though you may not want to hide it from say the government, the fact you work for huntington life science or GSK may lead you mobbing or physical attacks by (militant) activists. Just because you have nothing to hide doesnt mean to say you want your life broadcast.
In no way does you using your warrenty give the people at a repair shop permission to pick and choose what part of you life they can steal. I do not store passwords for my paypal (or similar) web site but there may many people who do so, which gives access to peoples cash. or more likley letters to the bank which usually contain enough imformation to identifiy the individual.
Its ok for the knowledgeable it prof to spout rightcous comments about needing to spend an extra 200 ukp on usb removable media and then configuring the OS to store everything on there rather than use your pc as its set up. But the point here is that the geeks should not be snooping. If they suspect a crime they should ask the police to investigate. This is like your neighbour breaking into your house and going through your stuff because you might be burring your wife in the back garden - or just adding a new flower bed - either way its worth going through your underwear.