I actually don't even play any blizzard games, but I thought I remembered them being sued over warden overstepping its bounds back in the day. I tried to search for it though and cannot find any evidence, so I guess I must have been wrong.

Edit: I did find mention of it on the Wikipedia article about Warden: http://en.wikipedia.org/wiki/Warden_(software)

On 23 June 2010 Blizzard updated the Warden Anti-Cheat Platform to version 2 - named Warden 2.0 - with World of Warcraft Patch 3.3.5.

Warden now scans Warcraft II and III game memory space only, with exception of a few tools.

Obviously it's a Wikipedia article, and no source listed for that claim, so who knows if it's accurate.