Don't know how true my logic is going to be, but I find it interesting, that student council Prez either had an indifferent or stoic reaction with other students and of course teasing attitude towards Bancho. However, when it comes to Toudou, other than the initial few chapter, she acts different. Like how she could tell there was something with how Rin talked, and after that she simply wants to go with Toudou alone to deal with Yanagi coming up with excuses or reasons for it. Although the author didn't expand on this scene, I do feel that Prez herself is jealous, though doesn't want to admit it or can't comprehend it. I know that later chapters do not expand on it and sorts of sets up Prez and Bancho l, but i sincerely hope the author does expand upon it.
Side note:I know Toudou is with Rin, but I also sincerely hope the author goes for the harem route.