I used to work for a large PC service centre, but never thought to take photographs of the PC's. I had some fantastic returns, one came in totally burnt out, the owner claims that it set on fire over-night, so we passed the PC on to the fire-brigade to have a look at, they found the remains of shredded paper. It seems the owner stuffed it full of paper for some reason. We sent it back with a polite note suggesting he didn't try that trick again.
Quite often we simply got PCs returned with the address label stuck to the case, no return address details, RMA number or anything. With these we would boot them up and have a delve round My Documents for some clue to the owner, if they wouldn't boot, or we couldn't find anything out we would put them to one side until the owner phoned up asking for their PC back. Some PCs on the untraceable rack had been there for a couple of years.