Hermione makes a valiant effort not to twitch as the book's gently tugged away from her, and gives another embarrassed smile. "It isn't that I'm not enjoying myself, really- just that I came out for some air, and- well, I had the book in my bag, so why not?"

Because it's overly solitary and possibly quite rude. She's not stupid; that answer is very much obvious to her when she thinks it out logically.

"Er," she says, moving on, from one uncomfortable topic to the next. "Anyway, Kate, I've...sort of got a confession to make." Best to nip the deceit in the bud, right?