A Noted Tolkien Scholar says that if I don't like the Hobbit trailer I should just not see the movie. (And there is Jo Walton, proudly standing far away from the entire set.) Sorry, that's not an option for me. Unless I decamp entirely from Tolkien fandom, I can't avoid this movie by not seeing it. I am going to be living and breathing its atmosphere wherever I go. I know, because I did that of its predecessors. Just as an example, I have this day alone received six broadcast e-mails from various friends alerting readers to the trailer. So I might as well see it, and be able to have and express my own opinion of it, instead of seething patiently through everybody else's, because you know they're going to be talking about it.
Also, I can't do the job of defending and distinguishing Tolkien's work from the movies without knowing what they say. Half my conversations about Tolkien with non-specialists in the last ten years have consisted of "that's what the movies say, but the book says this" or untangling some movie-born (and -borne) misapprehension, which I'd never have understood or figured out if I hadn't seen the movies myself. "Know Thine Enemy" the proverb goes, and thereby for my own protection I am forced into the theatre.