http://www.mtv.com/news/1864396/lois...medium=twitter
Lois Lowry on Taylor's role in the Giver
MTV:*Of particular interest to the MTV audience is Taylor Swift’s role as Rosemary. She plays a relatively small and crucial role in the book, but once you brought on Taylor Swift was it expanded at all in the movie?
[QUOTELowry:*The role in the movie is still a small role, but it’s a crucial and very important one.
I have a copy of the movie in its final stages here on my computer, and I had my two grandsons here for the Fourth of July weekend — they’re 13 and 15 ,and I showed it to them–probably against the rules–anyways, I asked them was there anything special that they liked best and one of them selected the scene with Taylor Swift.
I don’t think because of Taylor Swift particularly, but because the elements of that particular scene he found very gripping. So her role in the movie is much the same in the book, except in the book she’s only remembered… And in the movie you can see the memory of her. She appears in, I don’t know the technical term would be, but you can see her. And it’s very compelling.
MTV:*Do we get to see her sing and play the piano at all in the movie?
Lowry:*I don’t know if I’m allowed to tell you that! I will tell you, she does not sing. I don’t know if it would be an appropriate thing for her to sing. It would’ve turned the movie into a musical, which it isn’t! So no, no singing.
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If they're the only ones who care it'll still help do it's job and boost sales. This is actually a great idea, and seems like something she might actually consider honestly 
Just to help the next few months go by faster.
being performed once in while seems appropriate in this stage in her career.