Well I can tell you (based on recent experience) that it is very easy for hands and fingers to get injured or even broken if a horse pulls away when you are holding onto it's lead rope or headcollar. Theoretically you shouldn't hold the horse directly by the headcollar because if your fingers are wrapped round it, particularly if threaded through one of the metal buckles, they could be snapped. Likewise, you shouldn't wrap the lead rope around your hand because again your hand could get crushed if the horse pulls away - a panicked or determined horse pulling away is a very strong force! Even if you are holding the lead rope correctly you are likely to suffer a rope burn if not wearing gloves. Of course in real life people get lax (like I did last week) because their horses are normally so quiet and from time to time accidents happen (like when our old horse got charged at by another horse when I was fetching hi in, jjerking his head away and hurting my finger because I'd let the lead rope drape over it). Thankfully most accidents, like mine, are not serious, just silly.