User blog comment:B214/Volume 23 discussion blog/@comment-31137559-20170405211038/@comment-1359322-20170406113440

They're opponents so no matter what strategy Rias uses, Grayfia can't really scold her on the spot. Regardless of their real relationship, in the match you're no more than opponents. You can only counter your opponents' strategy as an opponent, not as a sister-in-law.