It's not cheating in the eyes of USNA. Some plebes-to-be may consider it such in their own minds and I understand that view. Others consider it a way to "get ahead" just like being meticulous in working out. The bottom line is that, is USNA wanted plebes to memorize large sections of RP prior to I-Day, they would send RP with the pre-I-Day materials. If they didn't want plebes to be able to memorize things in advance, they would change up the rates every PS. As Kierkegaard says, I don't think USNA really cares either way.
Just like the real world "stuff" that I found memorizing rates to have helped me with, the rates that I had to learn were split between enduring rates and temporary/changing rates.
As a Plebe, How is the Cow, Navy Ranks, The Laws of the Navy, General Orders, etc were enduring rates
Officers of the Watch, Menus, Sports Scores, The Days, etc were temporary/Changing
As a SWO, my "rates" included: Casualty Control Procedures, Capabilities and Limitations of my ship, location of all bridge equipment (sight unseen), CO's Standing Orders, etc as enduring rates
Current Equipment lineup, scheduled events for the watch, weather, Location of the Guide, anticipated/scheduled maneuvers, etc, etc, etc were temporary/changing
Getting an advanced copy of Reef Points would not help with the temporary/changing stuff