Many people teach their horse that if they are rude enough, they will get a food reward. Unfortunately, you have inherited such a problem and are now left to figure out how to change your horse’s behaviour.
I think the point I’m trying to make is that even though we talk about rewarding a horse for its effort, as an essential element of the training process the concept is entirely foreign to horses. How much this affects how we apply a reward will depend on how much emotion we attach to the term.