More likely they just didn't see any need to remove the gameplay logic for it. There's no event so you can't get it by normal means, so without cheat codes you'd never see it. Quite a lot of games have unused content in them - ideas that never got used, stuff that was cut to make a release, stuff that turned out to be too complex to be worth completing, bits of old debug or boilerplate code (Ocarina of Time has the code and model for a fully functional Arwing fighter, Goldeneye has a whole level that was probably used for testing).