Perhaps a multilevel setup for better weighting and improved autoflagging accuracy (<=5 characters, <=10 characters, etc.)?
Obviously, this could be extended to a much deeper setup (one reason per unique character count up to 15 for 15 separate reasons) but I don't think that's necessary.
Something like 5 or fewer unique characters in answer?
What happens when existing reasons are replaced? Do we lose all the feedback we have, or can we automatically regenerate the feedback data for the new reasons from the existing data?
I know it's complicated, but this might just work, and it'll boost autoflagging accuracy a bit.
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[ SmokeDetector | MS ] Blacklisted website in body, blacklisted website in title, link at end of body, pattern-matching website in body, pattern-matching website in title, +1 more: www.musclestrainrelief.com/testo-gx/ by Thister70 on askubuntu.com
[ SmokeDetector | MS ] Bad keyword in body, bad keyword in title, blacklisted website in body, link at end of body, pattern-matching website in body: Glamour beauty serum by asddx on meta.SE
[ SmokeDetector | MS ] Bad keyword in body, bad keyword in title, blacklisted website in body, link at end of body, pattern-matching website in body, +1 more: how a bodybuilder trains now by IODFH on askubuntu.com
@SmokeDetector f (the website is linked to on numerous other occasions, and it answers the (off-topic) question). It's unlikely the author is affiliated with that website. And it looks like the spam flags have been cleared - it was on -8 but is now on -3.
@JoErNanO was that Travel post with a link to rental24h.com spam? I wasn't sure but I see it's gone now. There's one other post (from 2016, and another user) linking to it.
[ SmokeDetector | MS ] Blacklisted website in body, link at end of body, pattern-matching website in body, potentially bad keyword in body, potentially bad keyword in title, +1 more: Platinum Light Teeth by RosieGough on askubuntu.com
tpu- by Glorfindel
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@DavidPostill if you're interested in Yet Another Userscript, install this one. It will add a 'Destroy spammer' link for users with deleted posts (but no not-deleted posts).
[ SmokeDetector | MS ] Bad keyword in body, blacklisted website in body, link following arrow in body, pattern-matching website in body, repeated URL at end of long post: Is it safe to utilize? by Wass 19 on webapps.SE
[ SmokeDetector | MS ] Bad keyword in body, bad keyword in title, blacklisted website in body, link at end of body, pattern-matching website in body, +1 more: This Shred fx is produced by Sawlyme on workplace.SE