I haven't even heard of such a thing. I've done a couple written Q&As, but those I think are fair, since I have time to prepare a thoughtful response and don't have to worry about communicating body language to a faceless camera at the same time.

To be honest, it sounds like a net lose -- it's a definite negative for a candidate, with perhaps not much benefit for the company (high noise, high false negatives due to the awkward environment).

My gut feeling is that I would immediately reject any company that asked me to do that, if I had the choice.