There have been plenty of articles recently like this one at Ars Technica describing the attempts by US Internet service providers to double-dip in their billing (charging both the consumer and the high-traffic websites they frequent). The reactions are usually outrage at being taken advantage of or defense of the principle that businesses can charge whatever and whoever they want for services... And in some way, both are right -- but I think that a simple analogy can illustrate how these ISPs are treading on some dangerous ground ethically, if not (yet) legally:
For most people in the US, Internet service is like living on an island with just two bridges to the mainland. Usually, one of them is a whole lot more convenient than the other (it gets you to usual destinations a lot faster, etc.) -- so, while there is a choice, it is a very limited and unequal choice. Through some quirk of billing, these bridges charge a flat monthly fee for a pre-agreed numbers over them in a pre-agreed vehicle size. So far, so good.
Where it gets interesting is when the owners of the most convenient, widest fastest bridge decide that, to supplement their income, they will charge a fee to the stores on the mainland that the bridge customers, visit and only make it easy for vehicles to reach those that do... Even more interesting, the bridge owners actually own some of these stores. For the most part, nobody notices anything, but some people are starting to question why the bridge ends in a two-lane road unless they are going to barbecue-r-us, the rinkydinkville general store or the godawfulplex movie theater, say. They can't help but wonder why the small fortune they pay to drive their Suburban across the bridge doesn't allow them to get Chinese for dinner, shop at Target or watch the movies at the good theater?
Can you really expect the bridge owners to keep their doorsteps pitchfork-free, even if the town sheriff can't think of a reason why it would be his problem?