MISSING_SUBJECT is, at least in my opinion, incorrect. The Subject
header is there, it do EXISTS. It's empty, OK .... but it's not MISSING.
You are in the realm of philosophy. I would agree with you that
semantically :exists is not doing what it would imply (by name) that it is
doing, since it in fact checks both the existance of the key and at least
one non-blank character under that key.
The drawback with fixing it at this point to do what it says it does is that
it will doubtless break existing rules. And when you come right down to it,
in most cases whether the key is completely missing or the value is blank is
pretty much the same thing as far as spam detection is concerned.
Loren
