Doubt about the quality of gold and its existence at all are prompting investors to demand their physical gold in place of 'paper' according to this story from 'Before It's News'. Here is an excerpt:

"As the result of 40 years of known and secret sales of gold bullion by central banks to suppress gold prices, demands are made by those who have allowed the US and to hold their gold and they are asking for physical delivery. After delays on requested delivery, the sale of melt bars, which are not good delivery, and the discovery of gold plated tungsten bars, owners are suspicious that maybe their gold isn’t really in a US or UK depository. As a result there is enormous pressure for delivery. We know there are gold-like bars at Ft. Knox. We do not know if they are real because there has been no audit since 1954. Furthermore we don’t know who they belong too. This has caused great concern for those owning gold and hence, a demand for gold bullion. The same shortage has shown up on Comex and the LBMA, where instead of physical gold delivery the exchanges are offering cash bonuses, not to take delivery or in the case of Comex are being offered shares in the gold ETF, GLD." Read the full story here, including an economic summary: Before It's News