The take-away from this thread is that the rules and laws are inconsistent from bike path to bike path, so if you want to run, walk, or ride on a trail unfamilair to you, it may be a good idea to check to see what the local conventions are (if not clearly signed). When in Rome, and all that.
I agree. If walkers or bicyclists are walking/riding three abreast and don’t go to single file when someone is approaching there is a problem or politeness. But assuming politeness, this method works much better. The walker may be listening to music and not hear the bell or the warning. Seeing the bicycle approach reduces the chances of the walker getting startled and moving the wrong way.
And if the bicycle overtakes from the rear, this maximizes the space between the walker and the bicycle.
Bicycles are wheeled vehicles - it only makes sense to use the same rules as you do for pedestrians and cars.