Trail (shared use path) courtesy tips

This is from Victoria BC from John Luton's Flickr stream. It bugs me to no end that there aren't "rules/etiquette" signs posted on DC's Metropolitan Branch Trail. Uniformly I have found that bicyclists ride to the right. But pedestrians are all over the trail, either walking in the direction of traffic or against it.

But since etiquette signs aren't posted, why should we be surprised?

(Otherwise, I love the trail--other than the lack of adequate signage generally.)