They don't need anticheat software. They need a special team of admins that are able to appear in any zone at anytime but be invisible in order to observe the reported characters. Very simple scenario: an admin receives a forward of a cheat report. Admin teleports to the exact XY coordinates of the player and observes them for some time. If the players performs an exploit while bein observed, the admin performs a ban/suspension process. I'm sure the admin could even have a window for monitoring chat box commands entered or even remotely monitor the .exe or config files to detect any abnormalities in CPU usage or unknown or anomalous code lines.