gladstone,
Drawing an analogy from your argument, it would mean, that the contents of a college text book bought by me, could be used by me in other works or cited elsewhere, without giving credit to the author of the content. Because, while
buying the textbook, I am buying the right to the content.
My point is that the authors of the content stand to lose a lot of money; test takers reading their ideas or original works, have no clue to the source of the content. Further, the test takers could also use this info, to benefit them.
Anyway, I think that the authors of the content, do need to be acknowleged, for their original work.