He's full of shit, right?
He's just going to come back at some point with a story about how his house blew up or his arms fell off or something, right?
He'll say he just need about a week to get things up and running, and he'll say nobody should deal with him outside of escrow (but he knows people will), right?
Then he'll skip with a small hand full of quick cash, and plan to do the whole thing over again in a month or two, right?
I used to do this, it used to be pretty easy. I stopped when comcast upped their security and self-served config files wouldn't work anymore. It has more benefits than just free cable; to trace you to a physical location (more than just pointing to what neighborhood you were in) would be a monumental effort.
They are real, I'm surprised you don't see them more often on these markets. They don't work forever, though, normally they have to be tweaked every few months. Google haxorware, that's the popular firmware I remember from back in the day.