In a post by Angel Munoz of The CPL on cached.net, responding to comments about the CPL deciding to use Painkiller as their 2005 World Tour game over UT2004 or other games, he mentions this about Unreal Tournament. Thanks BeyondUnreal.

People wondering why we did not pick UT 2004. First realize that Epic is a huge supporter of CPL. The CEO Mark Rein is a friend of mine and Cliffy B is on our advisory board. A wide range of aspects were taken into consideration, including publisher/developer support for the entire tour. Unfortunately, Epic is transitioning to a new publisher and it was not expected that their current publisher would help us in marketing the game/tour through the end 2005. Additionally, there is a new UT in the works, but it was not going to be available in the time frame we needed. Mark and I are still in conversations about the 2006 World Tour.