So the alternative is adding a header and move it to the spam folder
automatically on the basis of the header?
Currently I just want to 'warn' users that the message is possible spam,
they can decide to move such emails automatically to a spam folder by
enabling a sieve rule.
What would be an alternative method to keep such functionality without
altering the subject?
If SA sees the message and classifies it as spam, it normally adds (from an
example)
X-Spam-Flag: YES
X-Spam-Level: ********
X-Spam-Status: Yes, score=8.2 required=5.0
tests=BAYES_50=0.8,DKIM_SIGNED=0.1,
It should be trivial to look for the "X-Spam-Flag: YES" line.
