In art, we do this all the time.* It's called appropriation. Some people think it's a postmodernist thing, but it's not. It has a long and illustrious history. I reckon the cave painters busily ripped each other off. However, the examples I'm going to use are a bit more recent than that – from the fifteenth century.
In fifteenth century Italy, it was not uncommon (to say the least) for different painters to paint the same subject. Nor was it uncommon for a painter to take some figures or a compositional device another painter had used when treating the same subject, tweak it, and use it in their own work.
Sandro Botticelli and Leonardo da Vinci were contemporaries. They trained in the same bottega under Verocchio. They knew each other's work well. In 1475, Botticelli painted this version of the Adoration of the Magi:

Note the pyramidal composition of the figures, the row of receding ruins in the top left, and the standing figure in the bottom right (a self-portrait). Compare it with Leonardo's version from 1480:

The standing figure at the bottom right is also a self-portrait. Now, Leonardo's got pretty fancy with the figures, using a half circle as well as a pyramid for a much more integrated composition. And ruins in the background were pretty standard in Adorations, to signify the old pagan order of things that was swept away by the coming of Christianity.
However, I don't think I'm stretching a long bow to say that Leonardo's painting is a direct response to Botticelli's. They were pretty competitive. Leonardo is saying, 'I see what you've done, and I've done it better.'
In about 1500, Botticelli painted this version:

Note the figure kneeling in front of the virgin and child. Mentally reverse it, then compare it with the figure kneeling in front of the virgin and child in Leonardo's painting. (Click on the pic to make it bigger if necessary.) They are the same. Note as well the figure in red with a black hat that looks a lot like Leonardo (though it is also a general type). The stupid amount of figures could also be part of it: 'Outdo this!'
So I reckon Witi should tell those po-faced motherfuckers to fuck themselves. Take a leaf out of Hone Harawira's book!
*An interesting and revealing case is Picabia. When he does it with his paintings, the art historians call him a proto-postmodernist. When he does it in his writings, he gets called a plagiarist.
I should also point out that I only rip off the dead. They're my proper contemporaries anyway.