Remember though, the direciton of motion is not the same as the direction you are pointed if you are sideslipping the plane with rudder. Once the rocket leaves the rail, the sideways forces of the direction of motion would likely straighten the rocket out in that direction, making it follow your path, not your direction (if that makes sense). It's like throwing a dart out the window of your moving car, it straightens out in the direction the car was travelling pretty quickly since the forces from the wind rushing by are enough to stabilize it in that direction.
It only really is a problem where you are trying to aim your rockets while "crabbing" the plane though. I see people do it all the time but it's pretty easy to avoid.
-Soda
AH Trainer Corps.
