Don't know if this post will ever be found by anyone, or if it's useful. But figured I'd document anyways.
People say the cutoff is because they wanna eliminate the chance of a spliced or TAS'd run getting on the boards, but this game is extremely hard to splice anyways because of the HUD animations needing to line up perfectly, SpongeBob's damage animations needing to progress sequentially, needing to have the exact right amount of socks and shinies, etc. And who's gonna bother TASing a run for GameCube anyways? Even if you did everything in the WR route first try, GameCube would be off by minutes. It's not possible to get a new record on Dolphin, so I honestly don't understand the cutoff. Probably just general "Emulator isn't REALLY playing the game" BS. People tend to get uppity about anyone who didn't pay for a console being allowed to submit runs for whatever reason.