I think what the Canadian Dance Assembly was pointing out was that if someone choreographs a particular dance and posts it on YouTube, then someone else uses those moves in a performance of some sort, some credit should be due or some sort of copyright owed to the original person.
I think it would be very, very difficult to say who created a particular work of choreography or a dance. I even gave the example of martial arts.
I asked indigenous groups if it might cause huge issues for a particular community if someone were suddenly to claim copyright for a very traditional dance. There were some questions as to whether copyright would even apply to indigenous knowledge.