I agree Joe, GP is a useful tool to enable easy understanding of the rotor dynamics for basic users, much the same way the term centrifugal is used. Neither are actually at play in the rotor disc, although GP is actually a phenomena where as centrifugal is ficticious.
When teaching this subject, I like to use the rotor head of the UH -1H / B212. It has a rotor disc that is subject to aerodynamic precession as well as a stabilisation bar that is subject to gyroscopic precession. It is then easy for the student to see why one acts as a gyroscope as it is rigid, and why the other doesn't because it is free to flap.
