I've just started playing a translated copy of Mother (GBA version) today, and noticed that everything that's supposed to be generated randomly (barring stat raises when leveling up) follows the same sequence of events: What enemies appear in relation to one another and how far apart, what they're gonna do, the outcomes of physical attacks, whether or not Hippies' bullhorns or running away will work.
I've noticed this happen with certain other games before, but chalked it up to resetting on the emulator I played each on compatibility with their RNGs. However, I most certainly remember this NOT happening with Earthbound when I recorded an aborted playthrough months ago. I'm not even playing this on an emulator; I'm playing on a Nintendo DS, which does not have a reset switch (and neither does the Game Boy Advance).
If I had noticed this while playing Earthbound Zero on FCE Ultra five years ago, I would in all likelihood have exploited it by selecting Defend whenever someone was due to take a major hit.
How do some games' RNGs just stay where they are when the games themselves get reset or turned off, while others' reset back to where they were from where you last saved? How did this port of something originally for the Famicom get changed to reset its RNG instead of just letting it roll (or if that was also the case with the Famicom port, how did that change with the NES prototype)?