Student's paper is a photocopy but the title page is typed. Missing pages in a blue book may be a sign. Papers and notes on floor near desk. Notes may be written under calculators. Identical incorrect answers appear repeatedly on two or more exams.
Student leaves room during exam.
Many instructors are hesitant to report incidents of cheating, either because they do not want to be bothered or think only the student who cheated is actually harmed. On the contrary, many individuals, as well as the institution, are harmed by dishonesty. This is an easy point to defend. More problematic is getting professors to report cheating. It is actually quite simple to report an incident.