If they just hired a programmer to make a 3rd party bot program that patrolled towns like ragial already does, but this bot is in GM hide, has GM kick/ban powers, uses a detection method like RCX to catch people spamming chat at 30 lines a second, and ban them. Not too hard, really, considering a legit player using the legit client gets red muted long before spamming the # of lines required here.
They will just start pm spamming instead.
Best to keep on their current course and implement a client side filter.