She has the resources to fight back and make an example of them, and they have the resources to make it worthwhile.
They didn’t come to an agreement to use her voice, they used her voice. And they obviously knew it was a problem because they went back to her like the night before trying to get her approval again.
The correct thing to do was NOT use her voice.
You don’t get to steal something, get all the benefit from it (the press coverage), and then say “oops never mind it was just a few hours you can’t sue us”.
Why don’t we try selling tickets to watch a Disney movie “just one time” and see how well that goes. I don’t think Disney’s lawyers will look at it and say “oh well they decided not to do it again.“