enhancement to UNIX mail program

[utzoo!decvax!ucbvax!mhtsa!harpo!cbosg!dale]

I continue to be frustrated by all the wasted resources resulting from
mailing a response to a USENET article back through the path that the article
traveled. Does anyone see any problems with making a change to the
mail program (or delivermail in BSD) to parse the addresses of mail
addressees to strip off initial systems in the address if the originating
systems can communicated directly to a subsequent system in the address?
The only glitch that I can think of is that mail would need a way to
know what systems the current system can communicate with. I am reluctant
to give mail read permission of L.sys for security reasons. But it also
seems rather expensive to fork/exec uuname or some other program to get
the needed information every time mail is sent. Comments?