I think alot of scrappers know about the e waste scrap...

I just picked up 21 computers at an auction. None had hard drives, one was a completely empty shell, and in 4 of them whoever pulled the hard drives not only pulled the memory sticks but also pulled the CPUs. The only good news on the last 4 is they didn't know what they were doing scrap wise and dumped the heat sinks back in the computer, one of which was a half pound of 100% copper.

Never thought to check for missing CPUs before.

Starbits

if you can get a glance at the back of them, that'll tell you half of what you need to know. If the Mobo is missing, you'll note that instantly, and if there's empty slots where cards have been removed, that'll tell you more