@Healeighgee: Warden has been. Monitoring what's being tracked by the system is an important part of the process before banning in waves. We need to be sure the detections are accurate.
@Romzen: It's a reminder of the rules and a promise that ban waves will commence shortly. Nothing more.
@ArdenTDG: It's not as though this is something new. We tend to remind players of our stance against cheating before doing ban waves. For perspective, this blog was published within about two months of StarCraft II's release, very shortly before the first ban wave went out:
http://us.battle.net.../en/blog/809157