Thanks! That explains why the old receivers that I got from my sisters after they each cancelled Dish (in around that same 20 year ago time frame) still worked for all of their programming when I hooked them up to my dish. I wanted to get my programming activated on them, though (Dish did not yet carry locals in Columbus, Ohio where one of my sisters had her Dish account) so I still called Dish to get them activated on my account. The weird thing with one of them is that when I first hooked it up, it would only work for the audio music channels. It was one of the models that needed a software upgrade to get interactive apps, I think a 3800. I let it take the software download (making it a 3900) and at that point it immediately started receiving my sister's entire programming package.There was a trick a long time ago with the first generation or two of smart cards. If the receiver was removed from the data stream before the deactivation hit was sent, after a couple of weeks they would stop sending the hit. You could plug the receiver back in and all the channels would continue to work indefinitely. No need to try this today, quit working almost 20 years ago!
Now even if you have a valid subscription, keeping the receiver out of the data stream will deactivate it and you'll need to wake it up with a rehit.