Surely the inconsistency in twists and favoring certain housemates over others means that the producer can rig the votes. By rig I mean the producers mass voting out who they want evicted. I don't think that there is a rule that says that producers can't interfere with the votes by voting themselves. I can see this happening especially in cases of close votes where they want one storyline (ie Ash and Helen's romance) prevailing against another (Hurricane Toya).