MadMonkey: I think the difference between Knights/Bishops and Rooks in that matter is much more importante than between White and Black Rooks. And yet, they are all packed in the same category.
Most Baclk Rooks have AP's disabled, since they don't want to put up with the adds and/or there's nothing to gain in there for them. I also think it's fair to let Black Rooks enter a competition against as many players as possible - a dozen BlackRooks competing between themselves to win a prize is not nearly as fun as the same competition with over 100 players.

That said, I don't care either way because I have APs switched off