With the imaginary friends, also known as spamtraps, now more numerous than the inhabitants of their virtual landlord's home country, a greytrapping retrospective is in order.
This reminds me of my own screed of a much simpler document (an ASCII table generated as a printer test back in the late 1980s) that was not possible to render correctly some years later - https://bsdly.blogspot.com/2013/11/compatibility-is-hard-cha... - also contains a link to a further rant about other document formats that were supposed to be "standard" and "portable".
Making life harder for spammers does not necessarily require a lot of effort, if done correctly. Here are a few suggestions for how to use your spamd(8) on an OpenBSD or FreeBSD system that require minimal input but can yield noticeable gains.
Doing your bit to protect your own users and others agains scams, phising or other undesirable mail activity is good netizenship, but unfortunately there is a tendency to think that contributing in any way takes a lot of effort in addition to deep insight into all matters technical and social.
This piece is intended to give you, an aspiring or experienced OpenBSD or FreeBSD user who do not necessarily run a mails service yourself, a taste of some of the options available to you even if you do not want to expend too much effort.
That particular problem has been addressed in the more common architectures - syspatch was introduced in OpenBSD 6.1 (April 2017) https://man.openbsd.org/syspatch
