Society revolves around trust. Many transactions are carried out based solely on trust. For instance, when I return a library book I trust that this will be processed as such even though I do not receive any confirmation of this transaction. But trust is one sided in this case. To check out a book, I need to go to a libarian to have it checked out.
Our county library seems to have instituted a new "policy" concerning book returns. Instead of depositing books into a slot to be scanned by the libarian, apparently we can now just leave them on the counter. Unfortunately, I have been on the receiving end of having books on "overdue" status even though the books were returned and reshelved without having been scanned as having returned. Its too easy for a librarian to be distracted when books are left on the counter and forget to check them back in and to just put them on the cart for reshelving.
I realize that this mistake is only a very small proportion of the total number of books being processed but for people like me it would be nice to have a system with a receipt. I suppose it would be the same thing as going up to the librarian and having the books checked in. Of course, it turns out that trust is not really one sided. The library has to trust me when I tell them that the books have already been returned.