So if you have a Wii u, you can actually mod your system with Homebrew and play GameCube games using a special injector. I know emulators aren't allowed, but this is on an official console. So is it allowed?

I don’t think so. I’m pretty sure it’s the same as USB loading but I’m not 100% certain.

The WiiU is a criminal device.

The thing here is that you have to modify the console for it to be possible, so I’m pretty sure it would be banned.