Years ago I requested 6,000 kgs fuel for a quick early LON - AMS. Got to the aircraft to find a puzzled refueller waiting to make sure we wanted 9,000 kgs of fuel removed. It had 15,000 kgs on board from the night before, but the flight didn’t operate for some reason. Had we departed for AMS the aircraft would have been well above MLW on arrival AMS. Pity Ops didn’t know the FOB before scheduling that aircraft for a short sector.