This would add a payment log of every payment you have received or made in each server on Manacube. (A short command like /ballog or somthing could be added.)
This could be used to for money, mana, and cubits separately or all in one log. This could also have a timer on it that clears the oldest entries in the log every week or few days or so.
This would definitely help out if you are scammed and do not have screenshots, nor can access chat logs (And chat logs can be edited, so that makes this an even better solution).
It would also prove innocence if someone is accused of scamming but is innocent.