Electronic devices have to be programmed. It couldn't just accidentally make a sound when you held the Z Button. Someone had to record the sound, and someone had to program it to play when you held the Z Button. They also had to compose a third sound, and specifically program it to play only when all four Z Buttons were held. This was intentional, done by people with intentions, to serve an intention.
Nintendo Power is correct, it is an alternative boot-up sequence. An intentional one.
