Will a stick with no hand on it stay perfectly still poking up there in the air above the mounting point as the plane accelerates with rapid jerks in random directions?
Mike, you beat me to it! It's breakout force would hopefully exceed any likely in-flight accelerations.
This is independent of whether the stick's output is controlling the plane or not. It's a question about whether under very heavy turbulence the input to the stick from the effects of the turbulence is stable enough to fly the plane. If not and the pilot HAS control isn't it possible that the bouncing around could lead to improper or damaging imputs to the flight control system?
It is possible though, that under extreme turbulence, consistently accurate pilot flight control inputs in Alternate or Direct Law may be less easy than with a larger, less sensitive device having larger amplitude stop-to-stop movements e.g. a conventional control column - judged
without having any experience with an AB style joystick.