This was announced at Relic Online.
A potential in-game exploit has come to our attention. While we understand the desire to improve/change or otherwise make the game your own, and respect those with the ability to do so, we must advise against unsupported modifications to the game's files. Please be aware that modifying your game client is against the Terms of Service and will result in a permanent account banning
Be aware that if you are exploiting the games files, it might cause Relic to lock down these files, making some mods impossible to use. If you're cheating you might end up harming the community, so don't.