I suppose the 8th-place hitter occasionally gets pitched around to bring the pitcher to the plate, but I think this happens much less often than you might think. It is really only going to happen when there is a runner in scoring position with first base empty and with 2 outs in the early innings. That is a very rare situation. In every other situation the pitcher is going to go after Hanigan aggressively.
- If there is nobody on base with less than two outs they will want to make sure they get Hanigan out so the pitcher doesn't have the option of bunting him over.
- If there is nobody on base and there are two outs they would want to go after Hannigan to make sure the pitcher leads off the next inning instead of making the last out of the current inning.
- If there is a man on first base they are not going to walk Hanigan and advance the base runner too.
- If there is a runner in scoring position and nobody on first base but less than two outs they wouldn't walk Hanigan in that situation either because then the pitcher could still bunt everyone over.
- If there is a runner in scoring position and first base is empty with 2 outs in a late inning they won't pitch around Hanigan because even if they walked him the pitcher won't come to the plate anyway because the Reds would pinch hit for him.
So I think there is very little reason to suppose that more than one or two of Hanigan's walks per season are due to his batting 8th in front of the pitcher. Hanigan has a good OBP because he is a good hitter, not because he bats 8th.