The result will eventually be a mixture of trusted hardware and software, from server to client to GPU to display, that will not display the content if any of t

The result will eventually be a mixture of trusted hardware and software, from server to client to GPU to display, that will not display the content if any of that locked down blobby chain is not perfectly as it should be. Even the concept of "changing the channel" is something to eventually lock down in this way; don't let the users change tabs or modify the window or display state at all until trusted ad content has verifiably finished. The saving grace is that you'll probably be able to just get up and walk away until it's done, at least for some time.