I dont agree that it has to do with Luck. oDesk is highly recommended because of quality of contractors there. You fire guys at work too, dont you? Of course there will be odd cases and you have yourself to blame for that.

Once you interact with the contractor, negotiate the price followed by compete instructions, there is little scope of irregularity. Now that clients are billed ever week, not everyday, it's s a win win situation for both parties.