Depends, if it is agile then someone who is a developer could be working on art or someone in art could be doing some development style work.
Honestly you are right, but with agile I have found myself being a tester and doing some UI (which I should stay far away from "its off a pixel.... what do you mean I cant see it")
some of our UI designers can also develop. Just saying it is a possibility with the cutbacks we have seen due to the recession.