[M&M Guy]

Ok, this has been a kind of entertaining discussion.

Fwiw, I actually see and understand Scrappy's point about the defender arriving at the spot where the airborne player will land. We all agree that according to 4-23-4(b), the defender must be in the "landing spot" (legal position) before the airborne player leaves the floor. I think we are all in agreement in that.

His point is that it appears, within a strict reading of the rules, it does not provide any specific protection if that airborne player will land behind the defender, if the defender is still moving and not in the "landing spot" before the airborne player left the floor.

I agree with the practical application that it will be a PC or incidental contact in that specific instance. But, if I was discussing a literal interpretation of the rules, I cannot come up with any reason why one rule of guarding (defender has the right to move laterally or obliquely) "overrides" another rule (defender must obtain the spot before the airborne player leaves the floor).