I did mention that a borrower make a "deposit" for the cost of a borrowed book. The book comes back in the same condition it was borrowed - the borrower gets the money back. I think it would definitely enhance a borrower's memory.
The lender would give the borrower some sort of receipt acknowledging that the borrower has this money on deposit until the book/item is returned.
It might be tacky, but "forgetting" to return an item is tacky, also.