Great, thanks.

What about introducing a penalty for offenders, make it exponentially more expensive for them to post new stuff, until they “behave”

What about the other way round? Downvoting is expensive but becomes cheaper every time the comment has been downvoted already

Both are interesting ideas. I wrote up a huge doc on all possible angles to this, and this is what we needed for nearly any approach - negative feedback. It will likely need tons of refinement.