That’s a tricky one. I’m not in a position to give examples, but the subheading on the Discourse Shadowban topic sums it up pretty well: “The last resort for dealing with trolls that just won’t go away.” Also this:
My approach to the situation would be to add a note to the user’s account with Discourse User Notes to give other mods on the site a warning about the user and make sure they are quickly banned for any new infractions. I’ve never come across a situation where the user didn’t eventually go away.
I think we should be doing our bit to try and make the world a better place. The type of issue I’m describing here is dealing with users who seem (from my point of view) to be dealing with mental health issues. I’d like to know how to help them be better citizens of both the internet and the real world.