..don't be so shure. Doing some researches long time ago, they found out that there was sometimes already a slight - but nevertheless - an actual and feelable input on the sidestick from the pilot while just using the toggle-switch for doing calls, which has, while on manual flight, always to be corrected by the
PF -
Ok, but wouldn't this be noticed by a dual input signal? Then it would be quite clear that there was an inadvertent movement.
Seems to me that this can happen when your press the PTT switch without properly grabbing the sidestick. If you just press it, you apply a backward force which can move the stick. While on the other hand, if you grab the sidestick while pressing the PTT switch you automatically apply a counter force which should keep the stick neutral.