I do believe that game laws are enforced by the state. If it is a park, they can't hunt. The forest service doesn't have the personnel to manage hunters.
A white horse is more likely to get you shot than a brown one. The hunter sees white, assumes it is the backside of a whitetail deer, and shoots. When I rode a gray horse (white) I bought some hunter orange cloth and made him a cover for his neck and another to put behind his saddle.
If there is hunting going on, I really stay off the back trails. I am not going to be driven into the house all season. I probably won't ride opening day of gun season.