[fhars]

Actually, your comment clearly illustrates why the choice Firefox et al. made is completely wrong. The only reason the video doesn't show in your browser is that he had been forced to use javascript hackery instead of a plain video elements to override this braindead default behavior. If they had made the correct choice, it would have worked for you, too.

[SecurityMatters]

I demonstrate no such thing. It may be true that a better example of an embedded video element would show why it is a bad idea. I am open to trying other examples of properly coded video elements. My point was that the author did not demonstrate his point and it could be that Firefox et al made the choice for a good reason he did not understand. I still suspect that, but there is not good evidence here either way.