After reading page 4, "What's up, Maa-kun?", I'm convinced she knows, what she is doing. With her t-shirt tugged so tight and looking over so casual (but it really didn't look that casual), she messed up. That was too crude acting.
Now if the author have an inkling of drama planned, he will make it so that Manabu's crush are in that cram school.
Or just a fake distance crisis when the cram school are next building to the tournament.
@Qelix
Oh no, she certainly doesn't know. Manga like these rely on the fact that it's characters are utter morons. We wouldn't have this manga, manga like Hatsukoi Zombie or 95% of romance / harem / ecchi manga if the characters weren't so fucking stupid and arguably borderline mentally retarded.