Just a comment about trail hiking etiquette (on the Long Trail) as a fight nearly broke out ahead of me: just let faster people pass and move aside. No need to deliberately hold up folks who are either fitter or faster. You wouldn't do it if hiking in the summer, don't do it in the winter.
What the heck do people think they accomplish by trying not to let others pass them? I'm perfectly content to let people pass me as I hate when I have the feeling of people catching up to me.