Just about all Spam protection systems include headers in the emails that indicate a spam status. For example most WHMCS users are bound to be using either cPanel or Plesk hosting which has Spamassassin headers like this one:
X-Spam-Status: No, score=-3.0 [...]
It would be super handy to be able to use the Spam Control function built in to WHMCS to *also* search either the raw message data for "X-Spam-Status: Yes" or to be able to specify headers and regex results like header "X-Spam-Status" with a value that includes "Yes, score="
Similarly we could use the same system to detect SPF headers, DKIM, etc.
Yes, we could filter all of this at the control panel level, however then we'd have to periodically check the email account that WHMCS pulls from to ensure that messages in the Spam folder weren't false positives. And if they are, then how do we import them? If this is built in to WHMCS as described above, then we can simply check the ticket import log every day and import anything that was a false positive.