I repair people's computers. They bring it to me because it's a problem they can't solve themselves or just "don't get" computers.
I do tell them that I will have to unfortunately look at some of their data because depending upon what I have to do, may be required that reinstalled programs like picture and music managers, pdf's etc., will require importing or opening the files to ensure they work correctly.
Then helpful OS X features like Coverflow and thumbnails are going to display the file contents without even opening the file.
If I don't be very through and make sure everything works smoothly, they want me to fix it again or complain I didn't do a good enough job and it cuts into any profit or reputation I'm trying to make.
I tell them I will try my best not to be a snoop, will not copy anything for myself, but to give them all copies of their data, as I don't their files laying around incriminating me as being a snoop.
Also it just takes too long to go through everything they have anyway, I try to get their job done fast and correctly as time is money. But I have to move files and test things and may open a file or see pictures or something in that process.
I tell then if they have data on their computer that they can't absolutely let anyone see then I can work in front of them to remove the storage and hand it to them. Then arrange to install a new hard drive, operating system etc., provide them with a IDE/SATA to USB adapter. But it costs more this way than perhaps fixing a simple problem if it's that's the only thing wrong with it.
Some people have given me the go ahead and work on their machines, only to have reactions later about what they have on their machine. One girl had pictures of dead horses in a landfill on her machine and felt the need to explain why they were there, I guess she thought I would talk about it like she was a crazy nut or something.
Working on people's computers is a very personal thing, you get to know the person almost immediately.
If you don't want someone else knowing about you then keep those files on a external drive, because comptuers will break and trap your data and you will go into "paranoid mode" when someone has to access it to perform repairs.
Also you may want to check into local computer repair shops, get to know and feel you can trust certain technicians that they won't copy your data, pass your pictures around on the Internet or talk about your secret fetishes at the local coffee shop. But then again driving 300 miles to the nearest Apple store will they most likely will could be a better option. 🙂
Apple doens't provide a more personalized comptuer repair or data recovery service, you can't get to trust some unknown face behind the Genius Bar wall.
With Apple employees, one really needs to bring their hardware to them stripped of personal data or just be willing to accept they are going to look at everything and copy it all for their own personal use.
There is just too much repair volume going on for them to bother about wanting to earn your trust.