There was a case years ago, when a light a/c was in for a CofA or some such thing. Anyway to cut a long story short, the controls were disconnected for some reason. On completing the aileron control connection, they put some person in the cockpit to move the control wheel. Unfortunately this individual was unsure of left from right. The engineer(s) yelled turn the wheel to the right or left, in which he did. As the engineers were getting the opposite reaction, they expected, they called and said no, move it the other way, which they did.
Folks these mistake of crossed aileron controls, was never picked up until the resulting crash on the test flight. The company chief pilot was at the controls and another experienced pilot was there to take the readings.
The authorities tried to blame the pilot. However in stated in the FM that the controls should be checked for full and free movement. Nowhere was it stated the controls be checked in the correct sense. I learnt from that.
There have been several fatal accidents where an aircraft has attempted t/o with the external control locks in place.
Controls must be checked, for full, free movement in the correct sense.