This is an individual choice. If people want to register and become an Indian under the Indian Act, they need to make the decision. Usually it's the parents when the newborn comes who will make the decision to fill out the paperwork, provide all the pieces of evidence, and get registered with Indian Affairs, but once you're registered as a first nations person, you cannot deregister.
It's an important decision, and we understand that various factors influence the decision to register or not.