See, this... THIS is why I stay off paths. Actually, it's the same on roads except the skill level tends to be a very tiny bit higher on the road. A lot of paths have rules about warning others before passing. So on paths, I give warnings and have to contend with about half of them acting like squirrels and unpredictably leaping all over the path when they hear my voice.
But on the road, there is no such requirement, and I only call out if it looks like the person I'm about to pass may do something potentially dangerous/stupid. Otherwise, it's best to give them 3 feet and don't let them know I'm there until I'm in front of them.