I would like to point out that fanfiction would also fall under "derivative works" and most authors and companies turn a blind eye to that sort of thing.UltimatheChosen said:Personally, I suspect that companies probably won't do this for fear of alienating some of their fans. Besides, it's basically free advertising for them.
Also satire is IMMUNE to copyright claims in the US so if you have a mock up of a restaurant called Old McDonald's with day glow arches managed by a humonid cow from a place called Thunder Guff McDonald's or Blizzard could try to sue for copyright claims but odds are an reasonable judge would laugh the case out of the courtroom.
Now trademarks are a different matter and as a rule of thumb you really don't want to be using those as under US law there is this kind of "if you don't defend it you lose it" attitude.