Not all training takes place in the classroom. [We know that.] Good instructors usually learn greater lessions than the student. [Read "Illusions" by Richard Bach] This training story actually happened at the Naval Air Training Command.
It was discovered a certain flight instructor would detach his "joy stick" from its base near the floorboards during the flight and toss it out of the cockpit of his T-34 when he felt the student in the back seat was ready to solo. A student savvy to this stunt, thought it would be fun to turn the tables on this instructor. He went to Supply, drew out a "stick" of his own and hid it on the floorboards in the rear cockpit.
True to form, the instructor did his thing, making a production of tossing the stick into the "wild blue yonder." The student, pretending this was a training moment and he should follow suit, picked up his spare and likewise, tossed it out of his cockpit. The alarmed and panicked instructor, knowing immediately what to do, ordered for all to bailout and proceeded to follow his own order. The student calmly took control of the aircraft and the chagrined instructor watched from his parachute as the student proceeded to complete his solo flight and return safely to base.
No moral here, just a law of physics. "For Every Action There Is an Opposite Reaction." Then again, maybe there is a moral. Go figure.