The difference is that @stellabelle talks to them up front. They agree to her terms. That makes it fair. What people do on a contract and agree to is not for you or I to determine fairness. That is between the people the contract involves. If they are fine with her taking what she does, then so be it.

I can tell you if I wrote something and gave it to @stellabelle that 30% would likely be my biggest payday to date. I'd be ecstatic!!