My horse went from being “completely reliable tied” to “absolute problem child” in under 5 minutes, thanks to my mistake in improperly tying him too low while out camping-- he pulled back in a tie stall and broke a lead rope, then within a minute of me putting him back in there, he pulled back and broke the breakaway crownpiece of a halter. Did the same thing to the second halter a minute later. He wasn’t spooking, he just figured out-- quickly-- how to bust himself loose. So I put a regular nylon halter on him, with a regular nylon crownpiece (it was all I had left to use; we were 200 miles from home), and when he pulled back and met resistance, he really DID freak out, and managed to scrape the hell out of his head before I got him settled.
It was an absolute nightmare, and unfortunately 100% due to my own ignorance. 
Anyway, I ended up getting a blocker tie ring to use at my trailer, along with the good thick blocker leadrope they sell, and I no longer tie him at the trailer with a halter-- he gets a neck collar instead. Like Guilherme said, when they’re tied, they need to learn to be tied and STAY PUT; I figure the risks of someone getting hurt by my runaway horse (whether at a show, on a road with cars/trucks, etc.) outweighs the risk of him hurting himself from fighting a tie. Sad but true, and if that makes me a bad owner, so be it-- he needs to stay tied when I tie him. (Mind you, I don’t leave him there unsupervised, and I always keep a knife on-hand to cut ropes if necessary-- but he no longer gets to decide when he gets loose, regardless of how much he hurts himself trying.)
The first time I used the blocker tie at my trailer, Horse decided to go back to his old tricks and pulled back to break loose. The blocker did its job perfectly-- it “gave,” but only slightly; he only pulled it out maybe 6-8" before realizing that it was more effort than it was worth.
And I have not had one problem with him since.