@Logicfest -- such things happens very rarely but there is still a way to protect against that scam. Simply don't send the item until the money order clears and don't spend the money you gained through it until you know it is good. If that $1,000 money order turns out to be no good but you haven't spent a dime of it, then you are in good shape. Your bank will only charge you if the fake is discovered and you've only spent the money.
But exercising caution is always a good idea.