I played first base just as long as you did. I umpired a few years too. And I currently volunteer for the official charity of MLB umpires.

The intent of this rule -- and why it's a JUDGMENT CALL -- is similar to the new rule for blocking home plate. To give the defense a chance to complete the play. This rule is designed with the tapper in front of the plate in mind, where the catcher or pitcher is all but looking down the first base line and a runner in fair territory makes it pretty much impossible to throw to first base. THAT is what Smoltz was talking about when he said that players are taught to throw at the runner in that situation.

However, Peacock was roughly 1/3 to 1/2 way down the third base line and about three yards inside the line on the infield grass. This rule is not meant to apply to situations such as this; as someone else said, the rule is not meant to bail out an error. It's meant to apply when a pitcher or other defender is given no chance to complete the play due to the runner.

Now, as you've said, by the letter of the law Turner was inside the line. He was running where he shouldn't have been running for sure. But the obstruction was caused by the poor throw, not the runner -- and the judgment aspect of the call means the umpire essentially would have been right either way he ruled. Given the bad throw and the fact that Peacock had plenty of space to make the throw, I would have left this one alone.