If the ISPs become content providers, wouldn't they lose their status as common carriers. If they pay for ESPN's services wouldn't they become liable to the FCC for the content that they are paying for and possibly by extension the whole internet.

IANAL and I don't see an ISP losing its common carrier status over paying ESPN(It's too easy for them to buy the regulators.), but I can hope that something would stop this from occurring.

Not that I would advocate anything illegal, but couldn't someone set up a proxy from within an ISP that pays ESPN and open it up to those without access to ESPN.