That would be a good observation.
It would be a good way to judge the manners of the horse being passed too.
When I'm asked to be passd, unless the trail is very wide, like a road, I pull off trail and stop, to let them go by. Alot of people want to be passed while they keep going. That does require a lot of room, and that much room can be hard to find in some areas. Pulling over and stopping isn't so hard unless you're riding in a big group.
If a horse I want to pass is acting up tho, I stay back till the riders tells me it's OK to go on by.
There are so many things in a passing situation that need to be considered.
Becky
Indeed. None of the horses like it, the ones being passed, or the passers. And usually the riders goose them or jerk them right during the pass too, trying to prevent them from taking a pass at each other. So they react to that too.