If you're thinking of it as just a minute deviation of pitch as a constant, then yes no one can hear it. What you hear is the effect of mechanically speeding up then breaking, speeding up breaking, speeding up breaking, on and on and on to achieve the 0.1% number that affects the sound quality, and on many different levels not just pitch.
david
Actually its more like speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
,speed up- break - slow down - break
, speed up- break - slow down - break
,speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, speed up- break - slow down - break
, ….
david