Germany has had a fascination with American Indians for quite some time, especially after German author Karl May wrote stories at the turn of the 19th century about Winnetou (a fictional character) and the American West.
It's not surprising, then, to see some street buskers dressed in what is supposed to be American Indian clothing. However, it is a strange juxtaposition as the performers, who are not American Indian, wear cheap knock-off costumes meant to look like ceremonial regalia. This is rather disrespectful to the American Indian culture, to create a cheap knock-off of special dress that has spiritual importance. The music is not accurate, either.
We saw a group in Heidelberg doing this. It especially bothers my friend. I hadn't really thought about it much before; I tend to ignore buskers. However, I see her point.