I generally call out "on your left" before passing, except if the person is wearing headphone or ear buds. Wearing them means you won't hear me, so why bother. If I have to constantly slow down, then I shouldn't of chosen to be on the MUP.
Cyclists need to remember to share, the path with others.
But others need to remember to keep right, step off the path and not block it if they decide to stop and keep their children/dogs withing reach.