I am trying to answer my own question about seamless and sandbox for YouTube videos more in depth. Work has begun at a test page
Note that form elements do not work at all so far.
I would like to automatically determine if the user gets Flash or native video from YouTube. (Not what the user can get.) Under normal circumstances I'd suppose this is "none of my business" and it is perhaps impossible, because of security restrictions.
Is it possible? If so, how?
