Somebody'd figure out how to game a blockchain, or just render it irrelevant. You cannot engineer around human ingenuity. But it's always so much fun to watch people try.
That's not the point I'm trying to make. A simple way to test this system would be to allow the 'owners' of the gold to count it once in a while. As it is, there's no verification of anything.
A system with no transparency or verifiability is just waiting for abuse.