Gail did promise to cut people if they tried to fridge Charlie on her watch. (Or was that Zinda? I think it was Charlie.) I'm not sure if that protection extends to being made evil, though.
Of course, we haven't seen evil!Sin yet, so there's that. (Bedard really does like stripping those girls of their motherhood and pretending it's not utterly, appallingly criminal behavior on their parts, doesn't he?)