I asked a question on the
WJLA General Discussion Forum as to whether WJLA had purchased the equipment for DD 5.1. No reply after more than a month. I suspect they invested only in the video equipment. I'm not aware of any testing or trials of DD 5.1 at all.
Re: whether their HD video is fully operational, I'm not aware of that either. Their reliability, especially on weekends, is not proven IMO.