The header (for videos and other) was mentioned in [1]. I agree that is the way to go.

Adding a header to a web server or load balancer or app server if done globally can be done in a minute or two. Maybe 5 minutes for the intern not counting QA testing.

But you are right, the inverse is easier. I like that too. That was debated in the other recent thread.

[1] - https://news.ycombinator.com/item?id=47950091