Having automatic read out of various stats from the game like level and % and gold per player and bene and some rarer items should trigger automatic alarm if they reach for any given char preset treshold, like if you get too many exp points per hour or per day etc..
IMO that would be one of the best and effective cheat catcher. But that should only be accessible for GMs If there would be alarm, GM could discretely investigate just that one player and see if something is really suspicious o.O
If something like that is doable, it should be on the list to do once they get some breathing space, I imagine right now the time is all spent on more important things