trex,
Folk like you have no real capacity to think through all of the "what if's" and the implications for the well being of others around you. The safety rules are written for very good reasons and as such folk who think they know best and simply flout those rules have no place on modern aircraft and should be denied flight at all times.
In your scenario imagine if the aircraft is cleared for push back, the tug driver has a bit of a "heavy right foot", the aircraft lurches rearwards and you lose your grip on young grumpy who clatters to the floor.
If he's injured then young grumpy now needs off loading with all the inevitable delays thet entails and in the "where theres blame theres a claim" world with live in the airline finds it has another lawsuit from a Clampet Family member who thought he knows best.
If the CC tells you to do something there is always a very good reason for it and as such it is a passengers duty to comply.