Fishbed,. .. .if you think about structural integrity and control systems of large commercial aircraft, just think about flying level above 250 kts and then suddenly pull the elevator 11° for .5 secons, push 10.5° for .3, pull again between 10.5 and 11° for two seconds, push 10° for another one and then pull 9.5°. If you look out of your window afterwards, do you still expect to see your wings ??? They will be gone for shure !. .Exactly the same happens to a vertical stabilizer fin if you apply the same deflections to the rudder. You need no special pilot training to avoid such elevator deflections, so why should you in case of the rudder ? . .Lage transports are not designed for such maneuvers, they are designed to stand the loads normally acting with the least possible amount of weight at the lowest possible costs. Of cause you can build an airplane which stands any maneuver, but the DOC´s will be far higher as they are in the planes build today, so no operater will ever buy it. . .You can´t design a plane (or require such design by regulations) to stand any mistreatment, either by pilots or (much more likely in my opinion) by control system malfunctions.