It's not necessarily doubling the post, but if you play it attentively, the guard will have ample time to get out to the shooter. The issue is communication and who gets who. When the ball is skipped over, or is fed into the post, the guards have to know who they're covering on the perimeter. If they both come out to protect the initial shooter, suddenly another guy is wide open. The system is definitely a problem if you have young guys running it I think. I think the more you play in it, the more tough it becomes. I think that was a factor in why when Al went down, our perimeter D suffered so badly. Plus the loss of Rodney. Those are two guys with the quicks to get out to those shooters quickly, plus they have some time spent in the system.
Usually on defense, you're going to be vulnerable to something. You can question whether in this age of the 3pt shot whether being vulnerable from deep is a good thing, and I'd completely understand that. But it's not like this team gives up loads of points on a regular basis, usually offensively is where we have issues, so I'm not worried about Tubby's defensive system really.