Not everyone (for example: Karl Lagerfeld, assorted Kardashians) has gotten the memo about Native-American headdress appropriation. But at least one music festival has. Canada's popular EDM festival Bass Coast will be banning all Native-American-style headdresses on those who are not actually Native-American.
The Guardian ran this statement from the organizers:
We understand why people are attracted to war bonnets. They have a magnificent aesthetic. But their spiritual, cultural and aesthetic significance cannot be separated … Bass Coast festival takes place on indigenous land and … we feel our policy aligns with [aboriginal peoples'] views and wishes regarding the subject. Their opinion is what matters to us.
It seems unlikely that American festivals like Coachella or Bonnaroo could pull off a similar policy; vague protests like "but it's a free country” or “but I’m 1/16 Cherokee” would probably drown out the bands. Instead, it will remain all of our jobs to remind each other: Friends don’t let friends disrespect other people's cultures.