I am a Slingbox customer for 5 years now, and they tend to have the strange behaviour of not responding to our demands here on the forums or by any other means. I ve tried to reach them in the past with no success.
The feature that you are requesting is an old desire of mine. I ve read that they have not included as an strategy to minimize the legal risks involved, meaning, someone could deliver a law suit over them claiming copyrights issues.
But i do not think this is an acceptable response, because others have done this with no harassment.