This horse, Spooky, had decided that he no longer wanted to let anyone put a bit in his mouth, a bad habit he had formed and turned it into a game of, "Bridle me if you can."
Spook is a horse who did his foundation training with me, when he left he would accept a bridal with out balking. Where and how he picked up this bad habit is unknown. It does not matter, as you work with the behavior, not the cause of the behavior.
The retraining took about half an hour, the owner must reinforce it 3-5 times daily until he accepts it as his job without balking.