Re: MTGOX hits $570 "A bug in the bitcoin software makes it possible for someone to"
You're technically correct on that point. But it's only one exchange, mtgox, that allowed this limitation to grow unchecked into a major problem, you agree? The problem is removed if only sufficiently* confirmed transactions are accepted. (* I'll admit I don't know how deep into the chain they need to be before the risk is neutralized)
Your misunderstanding here is how it works
I deposit money into gox and withdraw it
mtgox sends it to my address and it get transaction ID A
I mine a block and include the transaction in my block, but as the miner I can CHANGE THE TRANSACTION ID TO B.
I then tell MtGox staff that transaction A didn't confirm. They check it and they see transaction A was rejected and will never confirm but what they don't realize is it was just changed to transaction B by me, so they resend the transaction.
Profit.
I'm not a dev, so I can be corrected on this one, but to my understanding the solution is for mtgox to check their outputs and keep track of them, before deciding to trust the claim and resend the tx.