This just-posted questionquestion on movies.stackexchange.com demonstrates clearly why this request cannot be adequately fulfilled.
The youtube link used is broken for me, as it probably will be for most of the movies.SE audience with the following:
This video contains content from Public Domain Compositions, SME, Warner Chappell and UMG, one or more of whom have blocked it in your country on copyright grounds. Sorry about that.
So, no one person is going to become the DRM expert for content we want to display from all over the world, and this wish or desire may be helpful to some members, somewhere, but not to the all members everywhere. In this case, even the link is useless to the majority of movies.SE users (defined as North America), and points out that an embedded youtube within our questions will fail just as dramatically.
I personally don't feel that an unfulfillable video block with the message inside to the degree of 'Go away, nothing to see here.' is useful or desirable. Let youtube continue to say it, once the link is clicked and the message is clearly theirs; incorporate a video window with that message within the confines of our questions, then the responsibility is blurred.