There are some subjects that are tested "open book", and that's not cheating because that's the way they are set up. But even in your example, if one student helps another, that IS cheating. Even open-book examinations have rules that must be observed.
There are some instructors who use open-book exams at our college but they also explain to the students that their open-book exams are also twice as long as the standard Scantron multiple choice exams, and more stringently evaluated.
I hope your instructor also emphasized that in the real world, employers don't tolerate cheating and stealing in their businesses.
BTW, there ARE real world bosses who will come up to you and say, "I want this solved, and I want it done
yesterday!" And bosses don't accept as many excuses as a teacher might.
No make-up exams or bonus points in the real work world.
I'm not picking on you, Vampy; just giving you another "real world" perspective.