Why does BYU not allow students to date other students?

They are allowed to date other students.. I have MANY friends who go to BYU and all are allowed to date. Why do you think that the BYU football team has more of its team members married than any other college? The LDS religion which runs BYU actually encourages dating while in college and even getting married. I don't know where you heard that they can't date, but they very much can.