Alot of games come out with a problem here and there. In fact, almost every game I've ever bought has had some type of conflict or problem installing or whatever. How do you get around these problems? By going to message boards and seing if there is a fix. It's easy to post on all the Tribes pages to un-install the demo before installing the game. People would figure it out. So in that example, there should be no problem with releasing the demo.
On the other hand, maybe the devs want to go out of there way to make this a flawless release. I don't think that's 100% possible, but if you can get close to that percent.. that's amazing. To sacrifice a day late of the demo release in order to fix the problem, that's fine with me.
I just hope it's not delayed till Thur or Fri. I want more than 2-3 days to text the changes and practice before the game is released.