I’ve only read the original post, not the comments that follow.
If a company is going to publicly broadcast, post, distribute, or publish something, they want documented evidence that ALL content is paid for and licensed by the party submitting the art/product/film/video/photograph/whatever.
In the film and television industry, they have lawyers that go over ALL content and clear it. They also buy liability insurance just in case something not licensed slips through unnoticed, or in case the content creator/owner sues them anyway. Hollywood motion picture studios have thousands of lawsuits every year from people/companies claiming their content was used and they weren’t compensated properly.
The demands for evidence varies between companies, some require original signed documents and receipts, some only ask for photocopies, some, for digital copies.
A film I produced and directed was a selection in the Cannes Film Festival. They wanted a document signed by me that stated that all the content in the film was properly licensed, paid for, cleared etc. - everything - every piece of music, every sound effect, the fonts used to create the title and credits, the art that appears in the film, model releases, actors contracts, location releases, crew contracts etc.
Why - because no matter what a company produces, whether it’s Harry Potter or Star Wars, there will be people who will sue them to grab some of the profits.
And if a movie/tv show/publcation does somehow use something not licensed, a judge can order that the movie or whatever is not to be shown - even if it’s a Batman movie that cost $200 million to produce.