For the record, here's how things played out (with some, but not all, relevant articles cited):
December, 2010: Sarah Lane does an interview
with Dance Magazine. When asked, "And how does it feel to be part of a performance that some critics are giving Natalie Portman rave reviews for?", she replies, "I’m not really looking for any sort of recognition. The process was a huge learning experience and I got everything I wanted out of it. But she deserves the recognition. She worked really hard."
Sometime in there, Fox Searchlight pulls/blocks the footage showing how Portman's face was superimposed on Lane's body.
March 3, 2011: Wendy Perron posts a blog
about the "black out" and the fact that this knowledge was being hidden.
March 11, 2011: Wendy Perron (NOT Sarah Lane) posts another blog
about the cover-up of Lane's work. In it, she quotes Lane as referring to the illusion that Portman did all the dancing as a facade intended to enhance the movie and saying that she didn't expect to be thanked. According to the author, Lane didn't realize until right before the Oscars how much of her footage they used. Wendy Perron, the author of the blog, is the one who uses terms like "exploited" and who is upset. Sarah Lane is just worried about how ballerinas in general are seen.
March 23, 2011: Benjamin Millepied
opens his cake hole
downplays Sarah Lane's work in an article
in the LA Times.
March 25, 2011: An article
appears on the EW web site quoting a more in depth interview with Millepied in which he said, "There are articles now talking about her dance double [American Ballet Theatre dancer Sarah Lane] that are making it sound like [Lane] did a lot of the work, but really, she just
did the footwork, and the fouettés, and one diagonal [phrase] in the studio,” he said. “Honestly, 85 percent of that movie is Natalie.” [emphasis mine; I'd have to say a good bit of the dancing shown was the footwork] This article is also the first one that I can find where Lane herself specifically addresses how much dancing she did, responding "Lane disagrees. “The shots that are just her face with arms, those shots are definitely Natalie,” she says. “But that doesn’t show the actual dancing.”