There's the bit in Charlie's Angels where Drew Barrymore tries to warn Sam Rockwell that Kelly Lynch is actually the bad guy by spelling out ENEMY on the scrabble board in front of them. The camera zooms in on it, at which point Drew whispers "enemy...", completely defeating the purpose of silently spelling out the covert message in the first place.
In the director's commentary on the DVD, violently enthusiastic director "McG" explains that they decided to add the whispered voiceover later, just to be sure that people got it. He doesn't say as much, but the implied continuation is "because our target audience is that fucking stupid."
They figured they'd better put the whisper in, just in case anyone in the theatre was spotted nodding in comprehension by their fellow movie-goers, who would doubtless then beat them to death on the grounds that "we got ourselves a reader..." And then go fuck their tractor, eat their cousin and marry a possum (or similar combination).
Nowhere else have I seen so blatant an instance of a film making it clear that it thinks you, the viewer, are a drooling moron. I mean, chances are good that you are, but that's not the point.
This is the point: McG thinks you're stupid. Hollywood thinks you're stupid. And that's why they're remaking Revenge of the Nerds.