I would like to make a note that no admins to my knowledge have ever taken actions against ghosts that cause trouble but I would like to make it crystal clear going forward that they are free to do so.
Examples of actions that ghosts can do that would be protected off the top of my head are as follows:
-Ghost controlled harmful objects
-Ouija boards
-"Ghost courts" during wiz events
-Ghosts with C4 attached to them during said events going where ever they like
This is a very minor change with the intent to provide clarity on how admins and the community treats ghosts in respect to rule 4.
Implementation
I believe simply adding this to the headmin rulings page is the right course as this subject is intuitive enough that it doesn't warrant any addendums on the main rules page.