Totally. I hate browsing to my local news site - SFGATE because it is always crashing my browser. They have multiple videos autoplaying and even blocking the content on the page. So frustrating.

Aside from all the problems this would cause with long-lived single-page applications and legitimate uses of high bandwidth (YouTube, Netflix, streaming radio, etc), I think you'd run into the same thing as the comment you're replying to is getting at: developers will find a workaround, and it may be worse than the thing you were originally trying to prevent.

I was recently researching the save-data header for one of my sites to not start caching video files on metered connections.

Its still a nascent thing only found in Blink browsers but at least its something.