I am no horse expert but have read alot from top trainers and horses seem to be "black and white" thinkers - either you're an alpha or a follower, with training they try what you ask or stop trying the behaviors you don't want, they are looking for a clear yes or no answer.
Situation: My horse stays in a pasture half a day (with round bales & 2 mares) and the dry lot next to the pasture for half a day. So one day I decided to get an armful of hay and throw it over the fence before I left. I did this once before, and the TB mare came over and acted like she didn't like it. Can't remember what she did but I was sure that was what she was communicating with her body language. A couple weeks later, I did the same thing (got some hay). She was at the end of the pasture (@ 2 acres) and came charging at me in a full run. I stopped and waved my arms and screamed as loud as I could at her. @ 15 feet from me, she swerved and went off, shaking her head. I got out of the pasture as quick as possible. After I threw the hay over the fence to my horse fo course - horse first, heart attack later.
I told the barn manager, and it's not the first time she's done this type of thing - pinned someone in a stall, trapped someone else behind a tree. The owner tells people she's "bluffing". I don't believe that for a minute. I think the owner is kidding herself and she has a potentially dangerous/dominant/aggressive horse. I've seen her ride the mare, she can be a handful but the owner is an experienced rider and the outcome seems good.
The TB mare's owner said her horse and mine got in a scuffle and she got injured. Well, my horse has had several scrapes and a couple hoof prints before (her horse has shoes, mine does not).
I might ask my horse be moved to another pasture.
What do you think?