Chris Mikkelson wrote,
| A *hard* link is completely indistinguishable from the original file.
Well, let's say that a hard link to a file is completely indistinguishable
from any other hard link to the same file, and it is impossible to tell
whether a given name is the one under which the file was created or one to
which it was later hard-linked.
However, a file hard-linked to two or more names is very distinguishable from
a file with only one (hard) link, and procmail, for example, will not deliver
to a plain folder that has two or more hard links.
Then again, its reasons for doing that have to do with writing, not reading,
so they wouldn't be logical as reasons for an MTA not to trust a .forward
with two or more hard links.