Im personally against halters on horses in turn out. However, I'm not going to take a halter off someone elses horse UNLESS they are in danger due to the halter like this one was (Being caught up in a fence).
I would free the horse, then take the halter over to the woman and explain what happened. Suggest a breakaway halter or something. KT apparently tried to do that but the owner wasn't home.
Personally, I wouldnt care if anyone was pissed so long as the horse wasn't caught on my fence. If she continues to turn him out in a halter, fine but I wouldn't just let the horse stay stuck there.