Joël
Volunteer Moderator
"guests" (and translations) is used ingame since RCT1
"peeps" is used by the community... There's no official relation to Atari, RCT, or Frontier (RCT3).
This discussion is useless because "peeps" was created by us!
At least RCT3 uses the word 'Peep Designer' for the in-game tool that can be used to design guests. Personally I didn't create 'peeps', nor am I using it.