Carrie doesn't have to play any instrument, she wants too. Carrie possess the best instrument she will ever need, her voice. As Randy Travis said about Carrie. Her vocals are her best instrument bar none.
People used to say that Carrie's band director and lead guitarist Mark Childres had a button near him, so he could mute Carrie's guitar. And Mark said no button existed. Plus Carrie is in control of what is happening on stage.
Like I said Carrie doesn't need to play the guitar or any instrument for that matter. She has the best instrument inside her. Her Vocals. Randy Travis said that as well at CMT special honoring Carrie. You could tell Carrie was embarrassed by Randy's comment.