Good point. If you don't trust the exchange, arrange for a client side stop loss function. At least no one would know exacly your stop loss order.
Do you know any good clients / front-ends that work with MtGox?
If you have a fixed stop loss limit, just enter an order before you get to bed. For a normal stop loss, where you want to sell after price is down a certain amount, I guess you can use any of the bots ( I havent tried them). You also need to decide if you want to sell for any price or for a minimum price. Personally I have a buy and hold stragegy, but earlier, when I traded in shares, I did not like stop loss because the suspicion that someone can trigger them for the effect. This can of course be done also without knowing the exact list of the stop loss orders.