Ha ha
Actually... if you look at planes like the [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXMUX7&P=7]Great Planes Reactor[/link], you'll see that the tail dips down way below the thrust line, and (nearly) half the rudder surface area is above the wings and half below. What this does is balance out the drag forces when the plane is in knife edge flight. On planes where this is NOT the case and you roll into knife edge, the rudder acts as an air brake and creates a ton of (pressure) drag ONLY on the canopy side of the wings, thus creating a roll or pull to the canopy. Many aerobatic planes have the bottom of the rudder just below the thrust line, and have an angular shape that (more) equally balances out the surface area.

(I like fluid mechanics=)