In classes where I had open book tests, the value of the notes was always mitigated by the time allowed for the test. It was always made clear to us that while

In classes where I had open book tests, the value of the notes was always mitigated by the time allowed for the test. It was always made clear to us that while you could use any resources you wanted, you definitely didn’t want to do that. You just didn’t have time. But if you needed to look up a particular chemical structure (example), it was possible. But you had to really know the material in the first place.