meetdilip Vbulletin had an add-on called "Miserable Users" which acted the same way, it was the first of it's kind and even showed the user weird error messages as well. XenForo adopted this feature in XenForo 2 natively, but I forget what the called it. It's actually part of user group creation as an option if I'm not mistaken π€£
To those that are interested in the Reddit-styled shadow banning system, it isn't impossible to create as an extension, it just takes someone with time and resources in order to develop it effectively π