Wouldn't work JB, because they activate the cards from there offices, so they know who is watching and the details of their card. The only way I could see a loophole is if someone worked out a way to piggy back someone else's signal, but because the signals use fairly heavy encryption they would probably need some means of scanning local signals, then a means of accessing the encrypted signal, so it would probably work out a lot more expensive than just paying for it.
That said, if I use a TV with a standard antenna in my house it will pick up the signals from my Satellite, albeit very poorly, so if there were some wireless means of boosting the signal strength if may be possible if there was a signal very local to you. Again the technology to boost a signal to that degree would be very expensive.