I have only skimmed the replying posts, and I do not claim to be an expert, but I have NEVER been instructed to 'let' a colicky horse roll. You do not want to horse to twist it's gut. However, there is a difference between say, a horse rolling because you just gave it a bath, and a colicky roll. Normal rolling, as I have been told, is okay. When a horse rolls over is when I have been told they are in danger of twisting their gut. You want them up and walking, but you don't want to over walk them. I would take caution when trying to stop a rolling horse though- a horse in severe pain does not know who or what you are, and may unintentionally hurt you.