Even if you share an internet connection with 3 other people, how much video can one watch? All four of you would each have to watch about 8 hours per day of Hulu to hit the cap. That's tough to do.
It's more against file-sharers. File-sharing is what really sucks bandwidth because people leave it on perpetually. It's also against people who should really be buying a fractional T1. At 809Kbps, you're using more than half a T1.
Plus, video is only going to become better compressed. H.264 is a great codec, but I'm sure we'll do better in another decade. So it isn't like it even hedges against higher definition video in the future.
edit: source of Hulu info: http://www.edn.com/index.asp?layout=blog&blog_id=4000000...