A ban wave is a large scale event (usually gaming related), in which certain parties/accounts get permanently barred from services, for major disruptions. An event like this will usually occur as retaliation against those who are unable to play the game normally, and resort to cheating and using cheating clients.
Runescapes ban wave:

Bot Nuke Day (Project named ClusterFlutter) was aimed to destroy most of the macros (bots) in-game. While this has been extremely effective (eliminating approximately 98% of the bots in-game), around 2% of the bots still remain, and Jagex is working on creating a second Bot Nuke, codenamed Optimus. Unfortunately, ClusterFlutterer has caused FPS lag issues and a few bugs for some players.
by dos_equis April 9, 2014
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