This is not as true as one might think. An official can do a good job on the court on a given night while possessing a very limited knowledge of the rules.
In most games, a tiny fraction of the books are actually in play. Also, it is my take that the number of questions on obscure things seems disproportionately high. Lots of questions about double fouls and point of interruption. I can count on my fingers all the double fouls I have ever called in 20+ years.
If you have two officials working a game and one made a perfect score on the test and the other barely passed, it may or may not be obvious which is which.

Then that is the fault of your state that would give a test that people all over the country have access to. It is not for everyone to know or not know what other states do or do not do. We have the test for weeks before we turn in the test which we can complete online. If you are smart you can figure out the actual answers if you review the test with other officials or if you get 100. And if your state feels it is cheating to hand out the test, then change the way you give out the test. We are in an internet age where just about anything can be accessed on the internet.

Our state completely changed the Part 2 Exam process to eliminate some level of "cheating" on some level. If your state cannot handle the fact that people might share the test in some way, then change your process. Not everyone is under that system and nor should they be. We do not expect other professions to follow all the same regulations from state to state, why would we do that in officiating? Most people do not work multiple states. If they do, you adhere to those standards or get out.

Peace