In times of crisis it can be physically moved, e.g. under threat of Nazi invasion in 1939-1940 the UK physically moved over 1,500 tonnes of gold from London to Canada ("the largest known movement of physical wealth in history"[0]), and infamously at the start of the Spanish Civil War the Spanish physically moved 510 tonnes of gold from Spain to the Soviet Union (never to see it again[1]).
[0] https://en.wikipedia.org/wiki/Operation_Fish
[1] https://en.wikipedia.org/wiki/Moscow_Gold_(Spain)