I've commented here many times about the simplicity on riding on my local rail trails, where the usage is very light - to the point of sometimes riding 20+ miles without passing another biker or walker. Thus I haven't had the problems that many people report on busy MUPs.
The other day I'm out for a ride, and being a beautiful day, there are more than normal trail users. Still well short of busy, but over every 5 miles I'm seeing about 6-8 people. Nearly all of them being recreational trail riders, with small kids or older couples out for a relaxing ride.
So I'm riding along, heading for home, just a couple of miles to go. I see a walker up ahead of me, a good half-mile from me, walking in the same direction as I'm traveling. I gradually come up on her. She's hanging on the right edge of the trail, walking a very straight line. No headphones on. My tires are crunching through the gravel. Walkers without headphones always hear me on these trails. Hard to sneak up on someone.
I pull out on the left and start to announce my pressure by calling out "Passing" as I almost always do. But for some reason, I don't bother. It seemed pointless, as I was making enough noise and she had been hugging the right lane for as long as I had seen her.
So right as I go to pass her, when I'm about 10' behind her, without looking, she steps directly to her left, into the left lane and directly into my path. I was shocked. I yell "Watch Out", squeeze both brakes, both tires skid briefly on the gravel, then I hard cut to my right, and start pedaling. Somehow I barely miss hitting her. I continue to fight for control of the bike for a couple of secs & then regain it and begin pedaling normally.
She yells out from behind me ... Sorry, I didn't hear you! But I was so focused on getting control of the bike, and in dealing with my irritation for her stepping in front of me, that I didn't say anything back. That is so unlike me. A few seconds later I wished that I had, but at the time, I had no words for her. I would have said that I should have made sure she knew I was there, but that she should also look before she changes lanes on a bike path. At least I didn't curse her.
My lesson learned is ... despite every factor suggesting that it was safe to pass, don't assume that you shouldn't make sure they know you're there. I should have said "Passing." And I should mount a little bell on my bike to make a more distinct noise. I had one on there, but it jingled as I rode over gravel, so I took it off.