Not sure all areas of Idaho do the same thing. District VI (Idaho Falls) uses the Part I as a tune up. It is handed out with the new rulebooks and everyone pretty much either does it on their own (open book) or just shows up at a subsequent meeting and receives the answers and maybe reviews some of it later.
Part II is a State requirement. A score of 80% is required to work varsity contests. However,... and this varies from year to year, the Part II is taken either individually or as small groups (basically your choice). Either set down with your buddies and your open books and all 'cheat' together for your community answers or be a loner and set down by yourself. Alone, you still have the option of using the books. I've found that once I look-up an answer for a single question, I get into a kind of mode where I want to look-up every answer... "How many outs per inning?" "I know I've seen that in here somewhere... thumb, thumb, thumb." Takes forever to justify every answer. It's a lot easier to forget about trying to find a rule reference for every answer.
I'm sure I look-up a dozen of the questions and in general it is in response to someone's question and me trying to justify my answer. I know the rules well enough to score above 80 without flipping the cover, but I generally find myself looking-up a few answers and getting an upper 90's score.
We take the Part II for baseball and fastpitch softball on the same evening. So, if you work both sports, it can mean a long evening of test taking... and a lot of thumbing if you get into that look-up mode.
Some years we have been required to take the tests as closed book. Things go faster then.