I don't see how anyone "attacked" the OP at all. That terminology is so overrused here on the DISboards.
What most of us are saying, is that it's 2011, and so you can pretty much find anything on the Internet, including movie clips, reviews and a myriad of blogs discussing scene by scene analysis of every movie currently showing at the theatre.
That info is there to be had for all...to blame or get irritated at the movie company or producers because one took underage kids to a movie, is totally not realistic, especially since this movie is 3rd in a series. Prior knowledge is all there...Not understanding movie ratings, ignoring movie reviews, or, not understanding how to assess popular media, is dropping the ball as a parent, IMHO; therefore, you take whatever comes your way. Although based on the first few minutes, this one sounds really disgusting. Although funny to some, it's not appropriate for 11 year olds to see, IMHO.
In the grand scheme of things it may not be a big deal, but it seems like it was to the OP, as she had to walk out, so again, I'm confused as to how any parent would take their underage kids to a movie that they had not seen, nor read anything about? Basing this decision on TV clips or movie posters is ridiculous, as the media's job is to manipulate people in order to procure sales. It's up to us to see through that and make an informed decision using the multitude of info that is available for this sort of situation.
It was great that she came on here to warn others, but her subsequent posts, are telling in that she doesn't seem to have taken any responsible for what happened. She didn't take advantage of the info that's out there on the movie, and in turn, she had to face embarassment at the hands of her kids, and the inconvenience of switching theatres.
As far as the Post Holiday Stress Disorder label, I don't think that's appropriate for us who are pointing out that this situation could have been easily avoided by spending a few minutes on the Internet.