Just imagine if our MC here had used his fucking head and, knowing that the headmistress was calling him in to talk about being seen with her granddaughter, had used this magical device in his pocket that can record video and audio to get the duplicitous hag cunt on record in an attempt to blackmail him.
That's a lot of leverage even if you have no plan of using it. A lot of ways to use it, as well.
Pride cometh before the fall, hag bitch.
EDIT:
Also, given how much Hakua goes on about being a "good girl," just sets off my doujinshi/hentai manga dialogue radar in ways that it shouldn't.