BASKETBALL Basketball Free Throw Rebounding Positions?

[Linton61]

I've noticed during the last two years that when opponents are shooting free throws, Gates has guards like East, Hodge, Bates etc. be in the rebounding positions on free throws while players like Carter, Vanover etc. hang back. Is there a reason he is sacrificing height and size at those rebounding positions? The only reasons I can think of is if he are relying on speed and agility to grab a board or if they are willing to give up a better rebound opportunity to set up full court pressure. Thoughts?