I am not an expert on Int'l racing, but when I raced in Western New York
High School leagues (late 70's) and Eastern Division I College Circuit
(mid 80's) it was definitely understood that if someone was in need and
you were there you gave them a pole (you do have TWO!).
I think part of it is the typical Nordic athlete mentality/personality. I
have skied for 30+ years and almost universally xc skiers say "hi!" where
as I have been a runner for 26 years and more often than not my "Hellos"
to other runners go UNanswered.
just observations.