Defensive player holds/waves hand directly in dribblers face- legal?

[hawkk]

Chuck-

Here's my theory -- and I'm guessimg -- on why this rule was put in. Imagine defending the post from behind by pputting hand in front of the eyes. This would be a rather effective strategy, if legal, as the whole point of posting up is to set up in a position and NOT move away from the defender. It would also lead to a lot of pushing and aggravation that has nothing to with the game. My guess is that is why the rule came into effect, as it is difficult to effectively put a hand to block the vision of a non-ballhandler outside of the post.