If you’re watching an ‘Exhibitionist’ & they get banned from Chaturbate, all will happen is that they’re webcam will go offline & the chat will be disconnected.  You will then be presented with the message: 

Access Denied. This room has been banned.

If you only see the webcam go offline for no reason & you can still chat, it means the broadcaster has only turned the webcam feed off or left the room.

If the broadcaster does get banned, they will need to email support@chaturbate.com most likely they will be required to go through verifications.