The majority of users will never go that far. ...
By the simple act of reading Slashdot, you've already placed yourself in the minority of users who are more likely to go that far. Know your audience; I specifically tailored my comment to this audience. But let's come back around to that at the end. First, I'd like to address this:
... So if you are going to do such a thing, first go over the fine print. Also be sure that you not want to use the service anywhere else, as that would make you a hypocrite. ...
This is a judgement call. Personally, I don't think you can assume that someone is a hypocrite just because they take measures to reclaim the internet connection they paid for, even if that person does take advantage of the service outside of their home network. I offered an example of a Superbowl party next door, but there could easily be any number of other justifications for taking such actions, perhaps even including paranoia over the previously mentioned copyright/porn issues.
But take this scenario as alternative example: Your next door neighbor and you both have Comcast. Your neighbor is a heavy BitTorrent user, and routinely saturates his own connection to the point where it's entirely unusable for anything else. You happen to know this because you were sipping tea on your back deck, and overheard him griping to his best bud over brews in his backyard, about how annoying it is that he can't play online games without first killing all of his torrents... and his bud advises him to just shift that torrent traffic over to a neighbor's WiFi connection. You sit silently out of sight as they go back inside, but you're actually fuming, and thinking to yourself, "Wait... that's me! WTF?!?"
The following day, your connection totally craps out... so he presumably followed his bud's advice. And being the intelligent Slashdot reading geek that you are, you promptly secure your network. Nothing at all hypocritical about it.
Or, to rephrase your earlier statement: the majority of users (even Slashdot reading geeks) will never go that far -- unless an adverse situation arises. Personally, I'm currently not affected by this issue, as I have Verizon FiOS, and (to my knowledge) Verizon has not yet implemented such a feature... but if I ever do find myself in such an adverse situation, you can bet that I won't feel the least bit guilty about cutting off access to whoever is leaching off of my connection.