Gina Miles was in the last one I watched.
The whole reason you go to a clinic is to try something new and different. So, even though she rides a certain way, she should be willing to try a different method in a controlled learning environment. If she wants to keep riding the exact same way she does now, what’s the point?
If she does go, she should use her stadium jumping tack and wear conservatively colored clothes and saddle pad. The horse must be well groomed and all tack must be clean and conditioned. The rider must wear spurs and carry a crop. Any bits with a curb action must have 2 reins. Rider’s hair must be neatly contained, and a belt and gloves should be worn.
I think the value depends on the attitude with which one anticipates the experience. For me, it was one of my greatest equestrian experiences.