To repeat a previous comment I made in my Notes on Carroll's talk, I think the difficulties that are raised in Matthew's comment stem from asking the wrong question: I think that calling a film philosophical is not only false in a syntactical, trivial manner (only humans think, how can a film be said to think? - this formulation is said to be meant as a short-cut; like "prendre un verre"), but in a much stronger and important sense.
Either you claim that some films are philosophical on the basis that they possess a special quality that leads the attentive viewers to a specific philosophical message (possibility 1), OR you claim that a film has special qualities that facilitate philosophical ruminations in general, without leading to a specific philosocophical message (possibility 2).
In my understanding, N. Carroll opts for the first possibility. His reading of Sunset Blvd consisted in enumerating the visual and narrative clues and techniques (evoking emotions) that lead the viewer to explore the question of the denial of mortality typical of human beings. And so he ends up, in my mind, doing the same thing as what other people do in the Open Court and other similar books, namelly "identifying" the philosophical message of a film. I could be wrong on this, and would welcome a discussion on this issue. But assuming that this is indeed what N. Carroll did in his presentation, I don't see how we can determine whether the philosophical message is in the movie or in the philosopher. Carroll would claim that it is in the movies (hence, the listing of cues). But listing these specific cues, while excluding all the others that don't support the said philosophical message, is an interpretative activity - one that involves the interpreter. And through this selection of clues and message, the interpreter plays an instrumental role. Hence the difficulty in determining where the philosophical resides. This first possibility then leads to an impasse.
The second possibility is also problematic. If you won't identify the message of the film (possibility 1), then you could say the film has a message but we don't know what that message is (so how can we claim that it has one if we can't identify it) (possibility A), OR you can say that the movie simply facilitates a kind of thinking, in the viewer, that is philosophical (possibility B).
I think this last possibility (B) is the only logical one. But it is very far from what N. Carroll did in his talk. I furthermore do not think that this makes the movie itself philosophical - it makes, rather, the viewer philosophical.
Many things, in the world, provoke wonder in us. Music, literature, nature, love, etc. Each may provoke this in specific manner. This is, I believe, a fruitful avenue for research for Film Studies: in what ways do movies facilitate philosophical wonder. This is, I think, a question that will lead to better, more accurate, more manageable and fruitful suggestions.