Great piece, Cam. I work for a mountain bike advocacy group down in the States, and negative user interactions are one of the things I dread.
Intentional or not, these conflicts generally end bad for only one user group- us.
I strongly recommend that every mountain biker takes a day off of riding and goes out on a fairly popular trail on foot. Having the perspective of those poor unfortunates that don't ride will really change how you behave towards them!
On the advocacy side of things, it makes it so much easier when riders treat other trail users like humans. We all want to be able to enjoy being out on trails.
So join your local advocacy group (If you happen to be in the Boise, Idaho area it's SWIMBA...) and spring for the Timber Bell.