My concern here is that it seems to signal a lack of respect for the candidate if the company expects them to complete a task with no matching employee time. Interviews are even; both sides clearly have skin in the game; a work-sample test could be given to any number of people at basically no cost.

This is somewhat alleviated by the knowledge that you do a phone screen with each person prior to that stage, but it still leaves me with something of a bad feeling.