The people in my area can be notoriously STUPID around horses. We've got people that will literally carry a baby around the parade route, while on their horse. And who knows what's going on off the parade route, or what some stupid kid might try. I'm afraid that the nearby sound of a whizzing rocket or firecracker might make her go nuts.
Now my cousin recently brought this issue to my attention, and her methods of fixing it weren't the greatest. They tied up their horse to a tree, and fired pop-bottle rockets off right beside him. He, understandably, went crazy, but they left him there. She said that eventually they got it so they could fire them at his feet, and he wouldn't flinch.
I'm not completely in favor of this method, since I'm pretty sure my horse would break her neck trying to get away.
How do other people get their horses used to fireworks? The same techniques can be applied to gunshots, I know. Do you just fire one 15 feet away, then get closer and closer until they stop flinching? I'd be interested to know if anyone has a good solution for this. I'm a pessimistic person, and I always want to be prepared for the worst case scenario!