I've been on both ends of the spectrum, but it's usually not a random stranger cheating on you. When that happens, you have 2 options: 1) don't give a shit and continue taking the test. 2) Be a dick and cover your paper. No need to cause a scene, no need to inform your professor.
Seems like this is some sort of retarded multiple choice exam anyway, so it really doesn't matter. On a REAL exam, with real questions, nobody can copy pages and pages worth of essays anyway, so don't sweat it.
Edit: And I love how so many of you guys are being racist - did you graduate from a Computer Science and Physics dual major with a 3.8? Didn't think so tools.
It's just SO disrespectful to me, the teacher, and the dude's parents. They are paying good money for what..him to come hungover to class, or baked and get nothing? I just don't get it!
Also, it's very disrespectful to me and it's not acknowledging how much hard work I've put into the class to do well in it. Think how you'd feel if you and a coworker were both paid for a job and you did 99% of the work. It's infuriating.
Edit: And I love how so many of you guys are being racist - did you graduate from a Computer Science and Physics dual major with a 3.8? Didn't think so tools.