A couple brought their computer to Best Buy to have the hard drive upgraded. They were assured that the old drive (which contained lots of personal information) would be physically destroyed.
Well, BB flat out lied. A few months later, that drive was bought at a flea market. BB didn't even bother to erase it. The person that bought the drive had everything intact, including bank statements, investment records and account numbers. This buyer was able to use the information on the drive to contact the original owner (who wanted it back.)
As far as I'm concerned, Best Buy is guilty of theft. If a corporation promises to destroy/recycle something on behalf of a customer, and then sells that something, they are selling stolen merchandise. They are (at least) in breach of contract, and should be held liable for all consequential damages (such as identity theft) resulting from their choice to not destroy the contents of the drive.
If you decide to replace a drive, do it yourself. If you're going to throw the drive out, physically destroy it. Drilling holes through it helps. An industrial shredder (which can shred a hard drive) is even better.
If your drive breaks and you try to get a warranty replacement.... Well, let's just hope it really is broken. I'd probably decide to forgo the warranty and just pay for a new drive, in order to keep it out of the hands of the incompetent pigs that work in computer stores.