The definition of who is, or is not, an aboriginal is fraught with controversy (consider Grey Owl). That said, in Powley 2003 SCC 43 the Supreme Court defined who may claim rights as Métis and that gives some guidance:
The Court did not set out a comprehensive definition of Métis for all purposes. It did, however, set out the basic means to identify Métis rights-holders. The Court identified three broad factors: self-identification, ancestral connection to the historic Métis community, and community acceptance.
Self-identification - the individual must self-identify as a member of a Métis community. It is not enough to self-identify as Métis, that identification must have an ongoing connection to an historic Métis community.
Ancestral Connection - There is no minimum "blood quantum" requirement, but Métis rights-holders must have some proof of ancestral connection to the historic Métis community whose collective rights they are exercising. The Court said the "ancestral connection" is by birth, adoption or other means. "Other means" of connection to the historic Métis community did not arise with the Powleys and will have to be determined in another case.
Community Acceptance - there must be proof of acceptance by the modern community. Membership in a Métis political organization may be relevant but the membership requirements of the organization and its role in the Métis community must also be put into evidence. The evidence must be "objectively verifiable." That means that there must be documented proof and a fair process for community acceptance.
The Court said that the core of community acceptance is about past and ongoing participation in a shared culture, in the customs and traditions that reveal a Métis community's identity. Other evidence might include participation in community activities and testimony from other community members about a person's connection to the community and its culture. There must be proof of a "solid bond of past and present mutual identification" between the person and the other members of the Métis community.
What can be understood from this community acceptance requirement is that in order to claim s. 35 rights it is not enough to prove a genealogical connection to a historic Métis community and then join a Métis organization. One must have a "past and ongoing" relationship to the Métis community.