LOL, I love the sheer number of mistakes in that example!
First up: the move described only provokes one attack of opportunity, per the Attacks of Opportunity examples in the SWRCR. Second, even with Combat Reflexes, Obi-Wan could only make one attack of opportunity on a single opponent in the round. Third, although we don't know Anakin's Tumble check modifier, I would not be remotely surprised if it weren't high enough that he wouldn't even have to roll - the DC is only 15, after all. (He's not moving through Obi-Wan's space, he's moving a good distance over it.)
Really, what they should have said is something along the lines of: George Lucas isn't bound by the d20 rules, or something similar. In any event, the removal of multiple limbs, as opposed to just one, isn't much of a stretch.
Edit: So you know what I'm talking about:
The example.