The real Janet and Margaret
I don't know about other people but I certainly wouldn't be happy and smiling if I was possessed!
During the interview with the real Janet and Margaret in this documentary https://www.youtube.com/watch?v=sls6pszMGfk Janet is asked by the reporter "How Does It Feel To Be Haunted"?
Janet replied we're not haunted just to be interrupted by Margaret telling her to Shut Up! Also Janet was covering her mouth while the alleged disembodied voice spoke through her. It's clear that Janet is goofing around with the reporter