I'm not sure if it's possible to have a wholly unique idea. And that's fine, really. We all build off of the various input we experience throughout our lives--environments, ideas, personalities, etc.
That being said, it'd be nice if people gave credit where credit is due, especially in the case of one-to-one copies. Perhaps I'm a bit sensative to this particular case as I care strongly about both photography and indie gaming. It seems that, in this case, an editorial for a major fashion magazine is copying The Path, an indie psychological thriller for the PC based on various versions of the "Little Red Riding Hood" tale. The shoot was done by Steven Meisel for the September issue of W Magazine. I'm guessing that the game has not been played by the majority of W Magazine's audience, so not too many people would catch this mimickery. Scrolling through the web page for that shoot, I haven't found mention of the game anywhere. Perhaps it's in the print version of the magazine, but I doubt it.
There's a lot of mimickery and copying and such that goes on everywhere, and that includes the tech world. We've been hearing non-stop about Apple vs Everyone, for example. I don't think that the hostility in court is necessary for solving this problem, though--I'm not even sure that it is much of a problem, so long as there are clear and honest discussions between the parties involved (I know, that's asking a lot from companies with old-school and aggressive business models).
But seriously, this kinda made me upset. When my game ever gets off the ground and out into the wild, I'd be pretty disappointed if someone copied a scene almost exactly, whether in a photograph, a movie, or another game, without any nod or credit given towards my game. It's not the copying itself that bothers me. I actually think this shoot would have been awesome if those involved had been honest about where they got their inspiration.