Indeed, I was briefly involved with the "bookz" scene as it was known at the time, over a decade ago, and the amount of --- completely voluntary --- effort that its members expended, especially considering the risks, was nothing short of amazing. People would go to their local libraries and borrow dozens of books to scan and upload, while also discussing on the forums ways to make the process go more quickly, and in general collaborating very efficiently.

When a few of them turned out to be from the same region, they would even organise "scanparties" where the goal would be to digitise whole sections of a particular library within a short time. I'm sure they raised some suspicion among librarians, and others would've noticed when entire shelves suddenly became empty, but to my knowledge no one was actually caught... and there were plenty of excuses to go around.

A memorable result from one of those is that there is now an extensive collection of car service manuals floating around on the Internet in various torrents and also as individual PDFs.