said by WhyADuck :

Well, I would thing that a lot of them would instead say "FU" to that broadband provider, especially if there were ANY other options.

But I think (or at least hope) that sooner or later congress and/or the FCC will get involved and make that sort of blocking illegal. It will probably happen right after some Washington bigwig is seriously inconvenienced by not being able to use an important high-bandwidth application.

I mean, when you think about it, this is somewhat like a telephone company refusing to connect calls to a competing phone company (CLEC), or charging long distance rates for what should be local calls. There have been phone companies that have tried such things and usually they are quickly fined and required to sign an agreement saying they'll play nicely from then on (if they don't sign, the fine is much much larger, so they always sign).