In chapter 12 Margaret is pivitol in 2 scenes. Willoughby has cut a lock of Marianne's hair. I don't think even Willoughby would have had the nerve to do this in front of Elinor or Mrs. Dashwood but once they leave the room, he takes the opportunity to clip the lock. It is important for Elinor to know this information because it is another thing in a growing list of evidence, as far as Elinor is concerned, that the couple must be engaged. Since the couple obviously had no qualms in performing this deed in front of Margaret, she is used as the purveyor of this knowledge to Elinor.

In the second scene in a bit of dramatic irony, at Barton Park, Magaret is wheedled into dropping a clue about who Elinor's particular young man might be. Elinor certainly could not have been cajoled into revealing anything nor Marianne, despite her exuberant impulsive personality. These scenes with Margaret, such as the 'walk' as well as these two might seem incidental but in each case important information is being relayed from character to character and/or to us as the reader that is important to the plot and characterization.

Because of the title which refers mainly, though not exclusively, to Elinor and Marianne, the tendency is to focus on their relationship as sisters. The above scenes are further evidence in my opinion that Marianne is just as close to Margaret as to Elinor--perhaps more so at this time. I think Marianne's perception of Elinor's diapproval in her and what she (Marianne) percieves as a lack of sensibility in her older sister often causes Marianne to distance herself to some degree from Elinor. As I have said, Marianne allows Willoughby to cut a lock of her hair in front of Margaret and it is obvious that she has confided her feelings about Elinor and Edward to Margaret with what appears a warning not to repeat it. Marianne appears to be more comfotable with Margaret right now because they have similar personalities and she does not have to worry about censure from her.