But that's my point: the movie itself might be shit, but the trailer does the intended job of telling me what the movie's about: Rob Schneider turns into a carrot, wacky hijinks ensue. The South Park joke works as well as it does because that format works so well at making you instantly imagine the plot of the movie (and how inane it must be).
If your movie's so shit that you think the only way to trick people into watching it is telling them less about it, you've already fucked up and deceptive/vague marketing won't save it.