A:  (Per Anton Treuer in Everything You Wanted to Know About Indians But Were Afraid to Ask)

Yes. Although there are prohibitions against the participation of outsiders in ceremonial events and customs for some tribes, powwow has no such official barriers. Furthermore, as the number

of Indians with light complexions has grown over the past few decades, many nonnative people may even be assumed to be native at powwows. The powwow emcee will announce to the audience if there is a special honor song or exhibition song for a certain style of dance. Otherwise, powwow music is considered and often called intertribal—open to people of all tribes and races.