Ok swissbob. This thread seems to have come back to life, and my bile is up, so I think I'll stick my oar ( pedals ) in here too. As a responsible mountain biker - as you correctly point out - I prefer to avoid paths which are clogged with doddering walkers, but sometimes I'm forced to use a shared footpath to get to and from the good stuff. When I do - I always ring my bell if approaching from behind AND I always slow down.
The walkers could reciprocate by turning on their hearing aids and not blocking the entire path, especially those surly buggers of the
"I'll show this biker who owns the path" school. This technique involves blocking the path and pretending to not notice the biker, even when approaching head on, ringing a bell, then feigning surprise at the last second, topping it off with and indignant scowl, like you own path. crap. You dont!
And regarding the Lycra, well, I cant say that I'm dazzled by the walkers in the fashion stakes either. Whats with those sticks anyway. You're not skiing.
And another thing! - Horses do much more damage than mountain bikes. And the frequently leave steaming turds in the middle of the trail.

I don't see you complaining about them!