If a student is caught passing the work of others off as her own, regardless of whether the work was copied from another source or another source wrote the paper for the student, the student will be charged with plagiarism. This, invariably, results in a failing grade for the paper. Some instructors will give the student a failing grade for the class should the term paper's failing grade not drop the student to a failing grade already.
Most colleges and universities have an "Honor Code" in place that explicitly states the consequences of plagiarism. In the case of Duke (and many other schools), after the charges have been made, the case goes to the school's Judiciary Affairs council for investigation. After the investigation is completed, it is decided whether formal charges, and the consequences that go along with them, will be levied against the student. Many schools suspend students caught plagiarizing while others will even expel a student caught turning in fake papers.
If the student is not caught plagiarizing, there are still negative effects associated with it. Should the student successfully pass the work of others off as his own, the instructor will have an inaccurate assessment of the student's abilities. This can lead to higher expectations for the student that cannot be met without continuing to plagiarize, thus increasing the student's chances of getting caught. Furthermore, if the student passes in a term paper that is not an accurate reflection of his comprehension of the subject, he may not be prepared to handle the subject later in his academic career or later in life.
The act of plagiarism constitutes two acts that are generally frowned upon by people and society at large: lying and stealing. When a person passes the work of others off as her own, she has effectively stolen the ideas of that person and has lied by saying that those ideas are hers. While the effects of committing these acts can vary from person to person, many will feel a sense of guilt, wrongdoing or, at the very least, fear of getting caught. Each of these effects can be avoided entirely if plagiarism does not occur.