[LieAfterLie]

Well the same thing applies in the forward direction. I was just contemplating the results of misjudging the direction of the feedback. If it's less than the setpoint and assuming the wrong direction, then the output will tell it to go faster, actually making it go slower and towards the real setpoint (even if in a more uncontrolled manner, going faster and faster until the assumption is correct). If it's more than the setpoint, it'll go the other way and won't stop, which is more of a problem, although being able to detect a wrong direction in either of these circumstances is better.