If said gold is not in their physical possession when the music stops, there will be a great many chairs missing with many venerable asses falling to the floor.
Why else would so many EU member CBs suddenly be calling for the return of their gold?
It is not as though the ECB or the BIS or BUBA or any CB for that matter can stop the freight train headed toward them, even though they think the FREE(gold) MARKET they want so badly will be the equivalent of that train crashing through the fragile, artificial system they've constructed out of faith and confidence.
Whether they intervene further or not, the interventions already performed have made matters worse, and further artificial imbalances will raise the dollar system collapse to a loftier height from which to fall.
Always remember ... that contracts stating the rightful ownership of gold in another's possession are but paper - dying empires will risk all when they see their "way of life" slipping away. If they will risk world war then they already risk the sanctity of contracts.
Gold reserves held for "currency strength" must be held in the way of possession, as competing currency blocs demonstrate all too clearly. Without possession for strength, depth of financial paper and electronic development is moot.
Those who have a stake in the coming change had better be holding their gold by the time they hear that whistle blowing.