>> This makes a lot of sense for archives and out of copyright stuff
I agree. I also think it was stated that folks are just scanning a single page. If that's out of a prose book, it's prolly okay.
I'm not one of your big city lawyers, and I haven't asked Roy's permission, but this here shiny PDF seems to say that stuff is mostly the same for print as it was when I was a whippersnapper.
So keep it to less than 10 percent of a boring non fiction book and the copyright goons won't come for you. Experiment with poetry, articles, and music at your own risk. ;)