With their new video for "Hymn for the Weekend," shot in India, Beyoncé and Coldplay stumbled into a controversy that's been centuries in the making: the cultural appropriation debate.

When is it okay to borrow from another culture, and when does the simple act of, say, wearing a kimono or Indian tribal clothing become offensive, a sort of identity theft? 

"Our clothes are our external representation to the world," said Susan Scafidi, author of "Who Owns Culture?" "So when you wear the clothes of another culture, you're representing yourself as part of that culture."