Sidelines are standard fare for our horses and while on the trail they prevent runaway horses over night. Some horses find it difficult to get used to them so you need to use a soft rope and bowline knot, a little longer than the sideline, to train the horse first. You need to pay close attention to your sidelined horse in training so it does not get a hobble burn. Do not sideline only one or two horses in a bunch as they will struggle to keep up with the bunch. We sideline all of our horses except the ones who have a difficult time with them, for these horses front hobbles are usually enough. If a horse does get a small rub you can change to the other foot.
Basically turns your hobbles into a three way hobble, front to back foot as well as front to front. Some horses can make make kilometers, even miles, over night in hobbles alone. Sidelines prevent the hobbled horse from jumping or running and allow only small steps.