Let me put it in a different way: Why wouldn't you try to sell your defective hardware for big bucks if it's not going to cost you anything?
When it comes to defective HDD's I can understand why people want to buy them, but they must be cheap as working PCB's most often can be found at a decent price (NOTE: quite a few things have to match, but at a good price it may be worth a shot to recover data.)
But there may be scams that require certain crap? Scam = Crap
Once I noticed that empty Dreambox boxes were selling for in excess of $60, and that wasn't like the "Xbox 360 box" those boxes seemed to be "Hot"...