The English language is a complex and varied piece of work, and
sometimes the unforeseen can happen!
For example, if you have gotten tired of having to clear out the most
common spams from your quarantine folder you may consider using
milter-regex in addition to Spam Assassin and your Virus app of choice.
And those 'erectile dysfunction' ads may give you the screaming
heeby-jeebies, so you might write a rule like:
tempfail "An unusual error"
header /^Subject$/ /[C[\!1IL]AL[\!1IL][S\$]/ei
That will kill all of that stupid spam instantly spam. And you might
think you're home and hosed. But then, let us suggest, you are keeping a
'tail' on /var/log /messages and notice a butch of mails about "Support
Specialists" getting temporary rejections... You might then revise the rule:
tempfail "An unusual error"
header /^Subject$/ /[\s][C[\!1IL]AL[\!1IL][S\$]/ei
<sigh> So, don't make this hypothetical mistake that may, or may not,
have been made by someone like me (but not me, I swear!).
Chris M