How can you copyright a color palette?

We recently added a Rights Management System that allows members to select several different licenses for the content they share on COLOURlovers, including color palettes. There is often confusion about how somebody can copyright or protect the rights to a combination of colors. You can't really protect or copyright the usage of a combination of colors in new works. Ie, if you take a color palette and then draw an illustration using those colors. But, what is protected is the arrangement of those colors into the rectangular shape that they are on COLOURlovers displayed along with their names. This is treated like a picture or work of art and can be protected... ie, you can't just scrape a bunch of palettes and put them as they are displayed here in a book you sell.