Now and than there is some loser who gets caught and maybe convicted because he is stealing bandwith from his neighbors who have forgotten to secure his installations (or had to return to default because after some upgrades nothing works as it should be)
But here i am reading a really funny piece about some ITgeek who made some changes so that the bandwith was seeing everything on his screen upside down or very fuzzy. I could think of some others thing you could do to his computer (passing through your router) but some of them would be clearly illegal. Some of the security guys here will probably have the same ideas. I don't think they would do it again.
It all seems a bit too difficult for people who are not that technical. Someone should put it into a click and play tool and call it 'eat that, bandwith thief'