Wisconsin creates the illusion of their arms being up thus they get away with crap. Iowa doesn't. Wisconsin knows how to advantage of the less than steller officiating that's going to come along when you have so many teams (thus an officiating talent pool that would be watered down)
They put their arms up and then the last second hit a guy with the arms and the refs don't see it for some reason plus the refs don't seem to get that even if you're arms are up you still can't just run into a guy when he's at a spot first.