Going back decades Britannia calculated the fuel cost for adding one large orange to their in-flight meals ... they diidn't add the orange
If any of you ever saw the TV programme 'Sky Truckers' featuring 'Cargo Lion', the crew were in a hotel bar, how unusual, and the F/E 'Trenty' was telling the story of one flight transporting elephants when at the last minute loads of bales of hay arrived, as he announced "Right, these have to be added to the payload and the fuel recalculated" the groom in charge would simply not accept that they counted as payload as the elephants were going to eat them during the flight
Wow, I just found 'Sky Truckers' on youtube if anybody is interested, I was young (ish) when we made this and a lot of alcohol consumption went in to it