I was watching ANH on ITV1 before, and when Obi's "He betrayed and murdered your father" line came on, it got me thinking, could Obi-Wan be telling Luke what he did to Anakin, but telling Luke it was really Vader. Will Obi-Wan betray Anakin???
When the audience watch the films in order they will automoatically know of old Ben's lies, and will think he is twisting it for his own good, trying to steer Luke away from the truth. This will make the audience start to dislike Obi and begin wonder if he is really as good as once thought. It would only be when Vader utters the "I am your father" line that the audience will begin to realise why Obi-Wan lied.
So will Obi-Wan somehow betray Anakin, and if so what will he do? Will Obi-Wan's betrayal be Anakin's final push towards the dark side?