There's nothing worse for a movie poster designer (or any designer, for that matter) than to have his/her poster "comps" shown to the public for feedback before a design is finalized.
Not only does this break down the review/revise process between the client (the studio) and the art director(s), it's usually a political/panic maneuver by the studio marketing department. They simply don't know what they want for the one-sheet, and haven't been able to get a design approved by all the countless people involved.
"So why not throw a few ideas out for testing, until we hear the answer we want." being the idea.
There's nothing wrong with public feedback and finding out how something "plays", but it shouldn't be a replacement for the studio and creative working together to produce a successful design.
Course, the "public voting" process for testing one-sheets never works. Several years ago, Fine Line Features had a "Vote for the Movie Poster" contest on their website. When the votes came in for a winner, they ignored the results and produced/printed an all new version of the poster, combining aspects of both the winning and losing designs. "Design by Committee" beat out "Design by Vote" in this case.