Originally Posted by
JSnake
As far as I know, EarthBound only checks the cart to make sure it has the right amount of SRAM. Bootleg carts and cart copiers add more, so the game throws up an anti-piracy screen. Then the game checks to see if the SRAM check was removed. If so, then it spawns more enemies. Earthbound does check to see if you're playing on a PAL system, but the result of that check is just another anti-piracy screen. In order to get more spawned enemies and the final boss crash, you would have had to see checks #1 and #2, which are just anti-piracy screens, and then purposefully remove those, triggering checks #3 and #4.
You might just be seeing a higher amount of enemies than you have on your previous playthroughs and mistaking that for 4x enemy spawn. The best way to check is see if Spiteful Crows are spawning outside the Onett Arcade after defeating Frank and his robot. If they are, then yeah you're screwed. But if not, you're safe and you're just being paranoid.