[cesarb]

You can think of the requests to fast.com as just loading the speed test control scripts and user interface. The actual speed test loads files from the same servers (with the same SNI hostname) used by actual Netflix video streaming. It wouldn't surprise me at all if the fast.com speed test loads real streaming video segments from these servers, the only difference being that it doesn't have the decryption key for these videos.

[bmicraft]

It would also not surprise me if dns requests for fast.com temporarily elevated bandwidth limits for netflix

[bradknowles]

It does. You're loading segments of real movies on Netflix that are not encumbered by copyright.

But they're intentionally otherwise indistinguishable from any other real movie on Netflix.

[therein]

That's surely how I would have done it.