andyjeffries
Senior Master
No offense, but whoever demonstrated that stance either wasn't doing an ITF stance or just had really poor equilibrium in general. It's pretty unlikely that someone who knows what they're doing is going to be pushed backwards as you described. I used to do stance training with my students and push on them quite strongly when they were in a walking stance and they were able to maintain balance.
I don't see how they could resist pushing with a wider stance. From a pure physics point of view it's easier to push something over if it's bases are perpendicular to the pushing force than if they are lined up with it, so surely the closer to in a line you get the harder it is.
Anyway, as I said, I'm sure RobinTKD won't mind me experimenting on him when we catch up in 2013 ;-)