Sorry DJ...I don't think I read your last post correctly or all the way through. But I think the answer to your question is pretty simple...they have the same names as the books and ARE attached to the books promotionally. Whether they are saying it's an "adaption" or "inspired by" or whatever is mostly irrelevant to the general public, whose first inclination is going to be to either compare them, if they've read the book, or assume its the same as the book if they haven't.
And Exo...I totally agree with what you're saying. All we can really do is assure as many people as possible that the film and the movie are nothing alike. In the case of I Am Legend, I've talked a couple people into reading the book by assuring them that it's pretty much nothing like the Will Smith film, except that the main characters have the same name basically. It doesn't have to be a comparison though. I actually enjoyed the film on it's own, and I think that's only because it was so different from the book. To me they are separate entities all together.
Anyway, speaking of last movie seen, and World War Z:
The movie was completely and utterly mediocre. The acting was sub par. The plot was underwhelming. It was too busy. It didn't give you enough time to be invested in any of the characters. Yes, it was stressful in some parts, but afterwards I had no desire to talk about how epically great or terribly poor the film was. It was just...meh.