Well said, Mayfield!
I personally use some "NH" concepts and groundwork, no particular brand, the general gist is pretty much the same no matter who's system it is. It doesn't take long for the horse to go from proficient in an exercise on a line to off-line. My guy knows the G & S drill really well, so every now and again I test him by doing it without a lead. I recently groundworked a pushy QH for someone, simple leading and personal bubble stuff, and he could do the simple exercises without a lead after 1/2 hour on-lead. The liberty stuff is simply a by-product of solid "regular", for lack of a better word, training.
I'm not knocking the video at all; the horse is trained to the eyeballs, and well, to focus and do her job in an exhibition environment like that. For me, it gets even more spectacular when I think of the on-line work that was done to get the horse to that point. Nice video!