After the big hack of Mt Gox we all became aware that there is nothing in place to prevent "flash crashes." Most stock, FOREX and other exchanges have features like trading curbs or other market volatility procedures to prevent such crashes - so do any of the Bitcoin exchanges have such curbs in place?
Also, if one exchange were to implement such a procedure would it still be effective if other exchanges did not? In other words, if Mt Gox implemented a trading curb and TradeHill did not, would this non-universal curb be effective? Would the effectiveness hold if the scenario were reversed? (i.e. TH has a curb and Mt Gox does not)