"No?" Luna smiled at her sister, "I imagine that they, or perhaps Faust herself, is keeping it a secret that we are in fact the offspring of Faust. Then if you include the fact that we are the 'daughters' of Princess Platinum, the pony who did actually imprison her, well... it doesn't take much work to blame her crimes on us. Then there's the simple fact that we agreed to leave her locked up where she was until we could contain her ourselves."