Likely nobody would even realize. It's not like the telcos would block sites. Instead, suddenly Netflix loads a lot slower than Comcast. Blame Netflix and move on.
Netflix might have the clout to do so, but a small startup which nobody has heard of never would.
Ultimately, the consumer mindset is never to blame their provider. They blame the website. If you come to my site and it's throttled, there's a high chance you'll click away and never come back.