Sure, you can, and it is alright. You would not accept a policeman controlling all your movements at home just to prevent you from scanning the book; would you?

Except it takes hours to scan a hardcopy.

> Thus readers can lend a book for a second, and keep a copy of it forever under their control Unless you were referring to this; in this case, how is this _Controlled_ Digital Lending?

there are machines to speed it up, but as it usually this, it only reaches a threshold when everybody, could and would buy it on the cheap.

Nevertheless, controled purchase would be out of the question in your case, too, would it? Or is that controled inasmuch digital lending can be persued?