So the baker decided to sell pencils as a side business. As a baker, he would loose cash on erroneous, duplicate orders of bread or pizza for which the customer refused to pay since  bread and pizza spoils.  But with pencils, even though he accounted for profit on a duplicate erroneous order, there was only lost potential or "accounted for" profit but no actual physical loss when the order was deleted. Bankers took a similar approach to deleting duplicate orders of  Tasmanian dollars as currency since the orders being deleted were just electronic and not physical in nature and there was much potential for booking new orders with a happy customer. Just let go of the "accounted for" profit on the pencils or the booked contract and sell more pencils another day. In spite of technological errors occasioned during the customer's use of the system that led to duplicate orders and the baker's potential loss, only the baker can decide how to prevent potential loss in the future and how to resolve his risk when such orders result in a potential loss on day one of the error. Relax and have a Cisco.  Then ensure that the baker verifies evidently duplicate orders in the future. The Thurstons and Howells usually only order 10 pizzas a month for the the local playboy bunny parties. An order of 20 pizzas was apparently a duplicate.