Sorry you are disappointed. I wonder if they are just wanting Troy to adapt to his new surroundings and the business of a show before they let someone ride him in one. Maybe you could offer to walk him around and acclimate him during the show.... then next show, you would be able to say "I kept him calm and I know what his trigger points are during such an event."
"Equine-facilitated therapy employs a form of biofeedback for practicing self-awareness, emotional management, and relationship skills that human role-playing exercises and discussion groups cannot begin to access." Linda Kohanov (The Tao of Equus)