Some established pullers WILL set back so violently and will throw themselves to the ground or come forward so haed that they will hurt themselves or you.
Tying a horse solid that has already learned to set back and break halters and leads can be a real challenge. Many of them set back and sull and fall over on the ground. They can choke down when they do this and must be released or they will die. If they are not tied to something above the height of their withers, they can 'pull their necks down' which is severe permanent injury. If they don't fall over or injure their necks, they very often quit pulling and lunge forward so violently that they hit their legs on whatever they are tied to So, breaking a horse to tie solidly that has already learned to set back and break things can be very problematic. Not only can they hurt themselves, but they can thrash so violently that a person cannot safely get to the rope to release them.
We have a VERY safe place to tie horses. We have welded old horseshoes to steel oilfield tanks that we use for grain storage and tack rooms. They are welded about 7 feet above the ground. We have big, heavy permanent tie ropes with huge draft-horse size bull snaps. But, if we tie a new horse, young green horse or a known puller, we run their lead-rope THROUGH the horseshoe and tie if off to a different horseshoe weld on about 6 feet away. We tie with a knot that can be pulled out or we can take a coupe wraps around the second horseshoe and just hold the rope by hand. This lets us release a horse that has thrown itself down without getting in close to it.
A better way to tie a known puller is to a big tree limb that has a little 'give' in it. Again, I suggest hanging a rope down from a ring that is well above the horse's head. Then, the lead-rope can be run through that ring and tied off over by the trunk of the tree. That way the horse can be released if need be. In my experience, horses are much less apt to throw themselves down when they are tied to something with a little 'give' in it until they learn to NOT set back.
I no longer get in pullers like I did when I trained for the public, but I have sworn that if I get another one in, I will use a 'Blocker Tie Ring'. I have seen them work without the horse to throwing itself down. They must be used according to the instructions. There are several ways to run a lead-rope through them and the 2nd or 3rd setting will work better than the first one. You also need to make a smooth 14 foot or longer lead-rope WITHOUT a knot in the end of it. A knot will hang up if the horse pulls the rope all the way through the ring and will break it.