When you hand over your computer to a technician, like those identified as part of the "Geek Squad", you have no idea what sort of person that computer tech really is or what they're going to do with your computer.
But, according to the anonymous Geek Squad member Cracked spoke to for their article, you needn't worry about the Squad stealing your vital information- because most of them don't have a clue how to plumb your hard drive for info.
In fact, even though they know what they're doing on paper they don't know what they're doing when they agree to repair your unit- so they look to Google for answers.
They do know all about how filthy laptops are underneath the case, and they know how to sell you on replacement parts and peripherals to help "prevent future problems" because many Geek Squad members are actually salespeople disguised as techs.
Read 5 Gross Things You Learn About People Fixing Their Computer at Cracked (NSFW language)