The attack in Thailand wouldn't have been possible without irresponsible lending by banks in risky real-estate speculations (where have I heard that story before)?
And how about when the Bank of England lost to a speculative attack by George Soros, in which he profited some 1.5b? http://en.wikipedia.org/wiki/Black_Wednesday
What makes you think people are not going to irresponsibly lend GoldCoins?
I guess it doesn't really matter, since no one is going to buy the GoldCoins in the first place. Faith in this escrow mechanism is not going to exist.