I don't know why people keep going on about this ,She's already called it her to her face ,just as Charlotte has called Carol a disgusting old bag to hers ,that's just the kind of "friendship" they have in there ,where they jokingly insult one another
Also on the Night in Question everyone keeps going on about ,Carol didn't exactly whisper said insult ,but rather yelled it at the top of her voice ,so i'm sure Charlotte heard her at the time she said it ,as Carol intended her to imo ,as she was only in the next room ,and would easily have heard it ,think it was Carols attempt at telling her "to pull her socks up" as it's just a game instead of crying cos she'd been nommed