Sometimes the students have no choice when studying for tests. Most tests in school aren't testing your knowledge, but rather your ability to regurgitate the lecturer's notes.
This assumes the students study only that material. There's nothing wrong with it. If your tutor tells you that these questions will either be on the test r similar to ones on the test then you'd be a fool to ignore it and try to study everything instead. Also, test scores rearely have any meaningful output with regards to how much most people actually know.
If the students decided to study like this, they weren't cheated by the school, just by themselves.