Then there'd have to be an inventory of Fort Knox, and an explanation rendered of where it all went.
Not sure that matters. All you’re doing is fixing a standard value measurement to the dollar, like fixing a standard measurement to your scales at home. When you don’t change the standard measurement of your scales at home, you can rely on what’s its telling you about whether you’ve lost or gained weight. In the same way, when you don’t arbitrarily change the relative measurement of the dollar, you can rely on prices giving an accurate reading of value. Not sure you have to have the gold locked up somewhere. The only good that might do is possibly keep the value of the gold static I guess, but I don’t think it would. Even on the gold standard, the gold itself would change relative value, but its relative to the market and dollar prices are still reliable. Reliable prices, like reliable weight measurement, is the point of having an external standard like the gold standard.