MvdV> The only explanation I can come up with is that the writers of P4
 MvdV> wrote it from the position that there *is* no cost. Which was
 MvdV> true for most if not all of the US and Canada at the time of
 MvdV> writing of P4.

how'se about trying this explanation on for size...

the writers of P4 saw that there is a cost in some areas and allowed for
that by making it (written in) policy that connections for mail are made
based on individual agreements... this is why the word "arrange"
was made part of section 4.1... 

to be explicit, the NC is required to accept inbound netmail for nodes in
his network... once it hits the NC's machine, how it gets to the
destination, whether delivered or picked up, is between the NC and the
destination machine...

one example that i was a part of at one time is that over half my network
was long distance to me... those folk "over there" had the option
of calling and picking up their mail or of picking it up from another
system in our network that straddled the boundry line between myself and
them...

later, i was able to get a "remote call forwarded" number that
was local to "that side" of the tracks... that allowed those who
were long distance to/from me to make a local (to them) call and connect
with my system(s) to pick up their mail...

)\/(ark