Another thread got me thinking maybe this post would be useful for some folks in the safety forum.
I think most negative interactions between different groups of trail users stem more from unawareness than anyone being intentionally rude. So here goes.
Horses tend to have a strong fear the unknown instinct,,, they also cant see that well dead ahead or dead behind.
#1 thing you can do when encountering a horse/rider team is open your mouth and speak up , any horse fit to be on a trail will instantly recognize a human voice and disregard the unknown object., no reason to stop, freak out,and especially dont hide behind a tree and freeze.. Just keep on walking your same pace , give the greeting of the day, most likely the rider will return it. If the rider is having issues for some reason, they might ask you to stop so they can move horse out of your way.

If you are passing from behind,, again human voice, but wait for a response from the rider .
"Hey how are you,,, OK if I pass on the left ? "
Give them a second to respond, some will turn and face you some may just answer,

Generally speaking equestrians dont really need any more than that.... There are a few that are a bit stressed,,,, But, like I said,, If you speak, and give a few seconds, you have been polite and done your part to share the trail IMO.

Ive got 1000's of mounted trail miles in multiple states so feel free to hit me any questions you might have.