Lanovran

On the road, yes, but not on a MUP (at least in the case of every one on which I've ever ridden). There, the general rule for everyone is typically "stay to the right unless passing on the left," whether walking, jogging, skating, cycling, etc., hence the use of bells and announcing one's approach.

I've had my own difficulties with getting people to understand/respond to "on your left," with the common exception of other cyclists. I have found that pedestrians usually respond well to "bike on your left" (as it's a bit more specific) or if I'm riding more slowly, I may say "pardon me/passing to your left." It seems like half the time when I use my bell, people turn around and look at the ground as if they think they've just dropped a coin or something.