I love Adrian Douglas's reasoning here.

"What most people overlook in the analysis of Central Bank gold sales is that it is a complete and utter farce that beats even the best Monty Python sketches. The Central banks have printing presses, and now in modern times computers that can generate gob loads of fiat money. It is beyond side-splittingly funny that we should take central banks seriously that they sell gold in return for the stuff they manufacture FREE.!!! Can you imagine the Saudis selling oil in exchange for sand, or Eskimos selling fish in exchange for ice or Paul McCartney selling an apartment in London in exchange for a Beatles poster autographed by Paul McCartney!?"