There are no limits for students who want to get knowledge and high grades. There are so many ways to cheat that a huge book on this theme could be written.
Some students are very creative in cheating under the professor's nose.
While a student, I saw one boy who had a tiny headphone in his ear. His friends who were outdoors were able to hear the teacher's questions through their headphones. They were looking up answers in the books and telling that student information he needed. On that day, the professor was surprised at the high knowledge of the boy. Unfortunately, not all of the students are lucky.