Alwaysbehind, the family HOPES he may have wandered off. Very big difference between thinking something has happened or hoping it has happened. If someone comes up to you and tells you your horse has died/gone missing/is caught in a fence, you think they're probably right, but inside you're hoping they've got the wrong horse.
If they are competing at as high of a level as it sounds, then there is the very real possibility that the horse could well have been stolen. I wouldn't even be surprised if it had been stolen by a fellow competitor. Some people will stoop that low to sabotage the person they feel most threatened by.