What these guys are saying are true I have a raspberry Pi myself and installed XBMC with Navi X and saw these channels. They are not legal (emphasis on the not) to watch. They are being streamed by people who have a legit cable or satellite subscription, or if it's a local channel, via OTA, and are streaming them on the internet which is then viewable by the Raspberry Pi with this extension on XBMC. Watching these streams are *NOT* put out by the original broadcaster nor are they authorized by the origional broadcaster. In the case of FTA, hacking dish network or bell would make you violate (here in canada) the radio communications act, in which you are deciphering an encrypted signal unauthorized by the broadcaster. In the case of this extension on the Pi, you are breaking copyright law. It is literally the EXACT same law that would get you in trouble if you download a movie off of the pirate bay... SAME LAW. In Canada that is punishable with a $5000 fine, in the US it is even more. So if you ask me it's not worth it, ESPECIALLY after the whole NSA Spying thing going on you're just asking for trouble.
So if you want to watch TV for free, stick to OTA, FTA (true fta that is, not this pirate stuff), and authorized streams over the net by the broadcasters.