HP stupidity

Remember that scene in OotP when Harry has detention with Umbridge for telling everybody that Voldemort is back?
He has to write "I must not tell lies", and the words are cut into the back of his hand while writing.

Apparently, and for no reason at all as far as I can see, this has been changed in the movie to read "I must not break rules".

Excuse me? Umbridge at this point is not concerned about him breaking rules. She doesn't want him to say what she wants everyone to believe is a lie.

I could have accepted if they had cut out that scene completely or changed it to something less violent, but simply changing the words is ridiculous.

Really, if they're so keen on making movies out of the Harry Potter books, why don't they do just that instead of tweaking the story around pointlessly?

(I found the link concerning this in huva's journal. Of course, now that the scene is shot it's pretty much pointless to complain, but it is just one more reason for me to not watch the movies.)