that would probably mess with your technique because the fact that you're moving and the bag is moving causes you to hit the pads at an awkward angle, making the punches more like slaps. and that guy blows.
I wonder if its a joke, the guy even throws a kick in there. Seems like it wouldn't be too bad if you can use it better, bob and weave under the smaller bags and come up with uppercuts maybe
The guy demonstrating technique sucked. "You'll learn how to block, evade, slip, counter, penetrate and react to timing." Hopefully better then the person showing the demonstration.