If you just stop and think about it, almost everybody in the Chunnin Exam doesn't really intend to finish it to become a Chunnin! And there's even more if you think about the Second Exam (the fake group Oro made after killing the real one)



Example; Oro's group, Sasuke, Gaara, Temari, Kankuro, Kabuto, those other people's names in Kabuto's group which i forgot, Dosu, Zaku, that other sound ninja girl, Shikamaru...