I think that just shows how unknowledgeable they are about horses and riding IMO.
I have been riding for 30+ yrs, have been doing training for about 5, and I still get the occasional lesson, to fix old habits, or to tune up certain things. Not to mention EVERY horse person always has something new to learn.
It is great to have that person on the ground to see things that you may not be seeing while riding. I find this to especially helpful when working very green horses...