From what I understand the genius of Only Fans isn’t in paywalling the content it’s in the personal communication with the creator. So having content re-broadcasted doesn’t really break the business model.

Still, it’s probably good to have a “please do not rebroadcast” attribute for events. I can think of lots of reasons you might want to ask respectful clients and apps to not spread something, the same way you can ask them to delete something.