I'd bet a lot of them probably did, and it just doesn't matter. Once the cops get the server logs proving that child porn picture A was delivered from such-and-such a site, that's pretty much proof.
By the way, the technology does exist to extract information even off completely reformatted hard drives. We're talking CIA and NSA level stuff (maybe they've bothered to give some of this tech to the FBI by now), but if they really REALLY want to know what used to be on your drive, they stand a pretty decent chance of being able to reconstruct what was on your disk at least three entire wipes earlier.
Which probably explains why the Pentagon's destruction orders for hard drives that once held top secret info goes something like this: Remove drive. Open drive, remove actual magnetic disk. Shred. Reshred. Reshred. Pulp. Dissolve in acid. Take remaining goo to army base and bury it, where it's protected 24/7 from now unitl the end of time.
Yeah, I'm aware of that. I meant something along the acid or small destructive (phyiscally) device on the hard drive. Self destruct button kind of stuff.
As far as this wiping thing goes. I got Norton Works a long time ago because I was having trouble. Installed the whole thing and used it for a while but have since uninstalled everything except the anti virus program. Norton's wiping utility offered "standard" or "government" as options. The gov't wipe if I recall inserted 0s and then 1s into all the blank space of your computer three seperate times and then did a random insert the final time before wiping the hard drive clean (if I'm not mistaken- I never used it). They can still get data after all that? How do they do it? If it's too long an explanation don't bother- but I am interested.