There should be a cmd like : /PendingBan.
Like if you health checked someone, and he logged off before you could ban him, you just write :
/PendingBan PLAYERNAME REASON
Then a menu will pop up asking if you are sure that this is the right name.
Once a lvl 4+ admin logs on, he can do /PendBanList which will show up a menu with pages.
In those pages you can see the name of the players which need to be banned.
If he clicks 2 times on a player name, it will ask you if you want to offline ban them, press Yes and he is banned.
The admin can move from page to page, and once a player has been banned throught the menu, he is automaticly removed from the list.