This is all way simpler than some folks think. Thing is, many people on a MUP, both on bike and foot, have earbuds in. They can't hear you. Doesn't matter if you ring a bell. Many walkers treat a MUP like it's their driveway. Whole families will stop in the middle of a MUP to have a conference, not even looking around. So #1, MUPs are more dangerous than roads. That's just a statistic. More accidents on MUPs, but more serious damage from way fewer accidents on the road. You takes your choice.
I have a riding buddy who was riding on a MUP when a runner wearing earbuds attempted to do a sudden U-turn right in front of my friend, so that he T-boned the runner and had brain damage even though wearing a good helmet. He used to take a baby aspirin, doesn't anymore. But that's what happens. Twice, children have darted across a MUP right in front of my cyclist wife who had to go off the trial to miss them. Luckily she only got a few scrapes and the kids were uninured.
The only defense a rider has is to ride extremely defensively, never assuming anything, including that the person in front of you has heard you hollering or ringing. My usual defense, besides vocal notification in plenty of time is to be going so much faster than the people I encounter that it doesn't make any difference what they do - or else slow down to a snail's pace if that doesn't look like a good choice. So far, so good, 25 years of it, no accidents. The other thing I do is to avoid MUPs like the plague.
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