Blah, pegging your horse to the ground should automatically protect it from theft. I mean you tied it to the ground, it's yours, you own it. Nobody should be able to take it when you have it tied down.
My horse also got stolen, I think it's pretty crappy that people steal horses. I mean it takes forever to hug them to 75% anyway, just get your own damn horse. It's just downright cruel to steal a horse, especially one that is pegged down and obviously has an owner.