Well, if you use the Unreal-Engine to make a mod for UT2k4 or 3, and it's for free (what I assume) it's completly legal.
And the problem I see with the Star-WArs or Alien engines is that there are rather small engines, which aren't well documented and have a small community, se we won't find help or helpers easily.
If you want to make a "real" 3D game I would prefer the HL2/Source engine. It's BIG, well documented and has a huge community.
But such projects cost time. We also could try and use the RPGMaker. (http://en.wikipedia.org/wiki/RPG_Maker) Which is smaller, with less coding and the graphics you can mostly draw or use a huge database. Puzzles etc are all possible btw...
So if we get a rather big team with experience or which is willing to learn, we can use Unreal, Alien, Starwars or Source Engine. But if we/you only are a few people, we can also make fantastic games with the RPGMaker
P.S. The link was about some big-scary american movie corporation sueing people in america.
1. Blame! is not licensed by a big corporation.
2. If the project leader is in a country where Blame! isn't licensed or which doesn't care, we shoudl be ok...