Don't underestimate the power of the ETF, they have an unlimited...

Don't underestimate the power of the ETF, they have an unlimited supply to work with and unlike us can't run out. The SPDR GLD EFT trust is supposedly back by physical bullion, however, I suspect that it is mainly backed by derivatives (futures contract and options) which they write themselves, so they are effectively printing their own inventory. I suppose the only thing that may bring them undone is if people loose faith in their ETFs and sell. They will then have redeemed those ETS for cash.....however if everyone sell out, the price of gold will crash and their investment will be somewhat protected.
They like a rigged game.