That's what the lead and brass are for. However, the size of the gold market is so small, it is doubtful that a sharp rise in price would impact any large bank to the extent that they would fail. Even a sharp decline in the dollar that would be implied in a gold increase wouldn't fail the banks. In the short term, it would increase U.S. export competitiveness. In the long term, we all pay with inflation.
Well yes and no. Not all that much true physical gold ever trades hands but there is a mountain of speculative paper derivatives out there that is all tied to the POG including our own currency indirectly. Huge loans have been made and every huger bets made in the gold market. Should be interesting to see who the winners and losers will be as the price moves up. I think that you will be surprised that even insurance companies like AIG have been playing in this "small" market.