The Mullet cycles in and out of fashion on a regular basis. It's a hard hairstyle to pull off, I agree completely.
Right now Scarlett is trying to find herself with her hair due to her pregnancy. She used to be thought of as a sex symbol with really sexy hairstyles. Now that she's pregnant, she has been spotted with short hairstyles. I guess she is trying to decide what looks best overall for her at this point in her life.