I was taught that pedestrians always have the right of way; on the road or the trail. Keep in mind that people with well trained dogs will usually move to left side of a trail because proper dog training teaches people to walk into traffic ( the left side of the road) and to always keep the dog on their left side (the safest place for the animal). Responsible riders and responsible dog owners get along fine, it's the obliviots that muck it up.