Until mod support is natively supported in the game, allowing any mod at all is tricky. There's no way in-game to see what mods are in use, meaning verification of a modded run would require that the video proof include how you launch the game, as a way to see the modlist. And possibly even more? I've never been a moderator.

Is there any reason you can't use the built-in arachnophobia mode? It replaces the spider visually and auditorily, doesn't it?