The key word here is "unauthorized". For each "culture", someone from that culture ought to volunteer to be the Official Authorizer. For a small licensing fee, payable by credit, PayPal, or Bitcoin, you could be authorized to wear an Indian headdress, a Samoan loincloth, a stick through your nose, or even blackface (though there might be a higher fee for that). The licensee would get a nice certificate that be could bring out whenever someone questions his right to "appropriate" someone's culture.
As a bonafide Canadian, I'll take the Canadian franchise. As an introductory offer, I'm allowing anyone who registers on my website to say "eh?" for free for one year.
That is actually quite brilliant. They would make great stocking stuffers too. Just like that buying your own star gimmick.