Brilliant. Well done again Xenforo.
You go to delete an account, it says "are you sure, it will delete all their stuff?" and you say, "Yes, that is what I want" and then all it does is change the user to a Guest and leaves their USERNAME AND ALL THEIR POSTS behind on the forum, except now you can't find them in ACP to do anything about it.
BRILLIANT STUFF.
So you Google the solution and it turns out the answer is to simply GO BACK IN TIME AND RENAME THE USER BEFORE DELETING
Awesome, thanks again Xenforo. Anyone know where I can find a ******* Delorian dealership?