Yes, they do normally hide them, although I have seen it take much longer for Dish to get around to finally doing that, especially with the NBA channels. I remember at least one time when the channels were not hidden until about a month later. Another time, the NBA channels remained visible all season long. NBA TV had been included in that preview. So, although any live games remained blacked out after the preview ended, I still had access to the rest of NBA TV's content (replays, etc.) absolutely free. I guess that Dish does still want to "advertise" for these packages by leaving the channels visible in the guide. This is why I still see the Boston Bruins (NHL) and Baltimore Orioles (MLB) channels, even without a subscription. I would expect the Boston Celtics channel to get similar treatment, even after the rest of the NBA channels get hidden.