My big guy (17hh, 5yo gelding) has a terrible habit of running off or dragging people when he's being led. If he wants to go somewhere, he just goes, no matter what I do. It happens mostly when I'm leading him outside and he likes to get away from me and run down the trails. I'm worried that he could hurt someone or run out into the road.
What do I do when he does that? I figured reprimanding him after I catch him again would only make it worse, so I just carry on leading him wherever I was taking him.