GP is a word used by roller-coaster enthusiasts, and simply means
General Public (as in what non-enthusiasts would say/do).
The word is also used as a
gatekeeping measure by some enthusiasts from letting their
passions be flooded with non-enthusiasts.
NOTE: People in videos tend to say 'general public'.
1)
Nemesis, at
Alton Towers, is
a ride not just popular with enthusiasts, but with the GP as well.
2) If you don't know what GP means, you're GP.