To be very accurate, they'd have to keep track of slip streamed versions. I had a maddening email debate with some friends some years ago over what the ARM said

To be very accurate, they'd have to keep track of slip streamed versions. I had a maddening email debate with some friends some years ago over what the ARM said. We were all using the same "edition," but we finally worked out that they were actually different. Stroustrup or his publisher wanted to correct something without actually changing the edition number. So for your scheme to work accurately they'd have to try to keep track of that. I think it's too risky, and would go with "scan the exact book in."