Al this may be quite true however I think it's because full scale airplanes have roll and pitch coupling when rudder is applied. On a high end pattern or IMAC airplane we strive to eliminate these tenancies. On a well set up aerobatic airplane when you give a rudder command you get yaw and nothing else. This is why when you look at an Extra 300L competition model you will notice some scale deviations. Most have the engine lowered, all have the stab lowered and it's usually on the thrust line, the rudder has more cord on the bottom and the wing has been raised. All these things contribute to the goal of having no control cross coupling. As far as not holding rudder but thinking we do, not buying it. There have been times when the wind is strong enough I can see my airplane 15 degrees off from path of flight. If one does not hold rudder in a cross wind then with each pass he would be getting blown inward or outward. Some can be corrected in the turn around maneuvers, but eventually you would either have the judges looking strait up or squinting to try to figure out what the dot 200 yards out is doing.