The geldings in the the pasture and my own horse like to tug blankets up the neck, so my solution is to tie a twine tail strap that’s shorter than the Rambo ones for the culprit that likes to get everyone to pull on his blanket.
Also, make sure you are using the extra strap on the underside of the tail flap for the tail - it helps them lift the tail flap and tail together so there’s less pooping on the legs. However, there will just be the position of some horse’s tails and where the seam of the tail flap sits that will cause the pooping/peeing on leg. My horse has a low set tail and does ok with the blankets but poops all over his legs when we are riding.