If they are under my control, they are to act like a good horse,
and behave.
And if they are being properly lunged, then they will. After all, that is, if you ask me, the PURPOSE of lunging a horse. To teach it balance and control and how to respond to cues.
...and if they ARE behaving, why are they being lunged in the first place? They ought to aready KNOW the above concepts before they go to a public event.
I lunge to check soundness, or for the vets at our NATRC rides.
I will trot a horse on a circle to check soundness, and the lazy man's way to do this is to stand in the middle of the circle with the horse on a long line, but it is not the only way (you can run around the circle with the horse if you want); however, it is much easier to do this with the horse if you have taught it to lunge (since you cannot reasonably check soundness if the horse is just galloping around on a circle bucking and leaping).
..... indeed - but it is much easier to SEE the horse's movement when one is not trotting along (or for those of us on 1 1/2 good legs, being dragged)next to the horse. From the distance, one can better see the movement AND the comparison left to right. A horse may appear fine to the left but demonstrate a bob to the right. I can see my horse much better when I am standing in the center - nothing lazy about it - just a better view.