I get what your saying, and your probably right, but, I would argue that the scope of the TDK campaign is larger than the NIN effort, and even if there was no "grand prize" like a premier for instance, all of us would be thrilled to get more memorabilia from the film...that doesn't seem out of line considering we've been awarded newspapers, cards, masks, and IMAX passes already.
Don't get me wrong, I agree that the movie is the great prize at the end. And we'd all play along if only for the experience of solving puzzles and chasing cakes...but getting more fun rewards doesn't seem like expecting too much.