This explanation was posted some time ago by ei8tohms and answers the question - FYI
Whether or not a non-hacking movement can be made to stop the second hand with some retrograde pressure on the crown is dependent on the tension on the cannon pinion, the slipping clutch that allows the hands to be set independently of the driving train. In short, if there is enough friction on the cannon pinion, you can stop the watch by putting enough pressure on it in the backwards direction to overcome the power of the mainspring. If it's a little too loose however, you won't be able to overcome the driving force except perhaps when the watch is only partially wound.
Most manufacturer's feel that a "properly" tensioned cannon pinion should be tight enough to allow the user to stop the watch, but it's not universal in my experience, and certainly they can get little looser over time.