they are purely voluntary and have no legal standing. Also with Jewish courts. And freemasons. And some private members clubs. People are allowed to make rules for their own associations as long as they don't oppose the law of the land.
So yes, publishers weren't up for paying Colleen Doran an advance to cover the creation of the Good Omens graphic novel. So they kickstarter it instead, and raised over two million so far, a comics record for crowdfunding. Don't bet against @neilhimself@ColleenDoran@terryandrob