Comcast? I don't know if that is such a good idea.....
Anyway, You know I had a customer that had this very same problem. I had to look at your state location because I thought you were my customer. Anyway, The same thing was happening. They said it needs re authorizing every time they turned the box on. They said they turn it on only on the weekends when the grand children are over. It's not used during the week.
I asked them many times if they unplug it and they say no every time. It is on a power strip behind the entertainment center. As a test I switched the receiver with another they had in another room. The same thing is happening to the switched receiver. The next week I replace the LNB and switch and it still did it. Then I replaced the cable to that room, Still did it........So I again asked if they turn off the power? They said no......... So I had them walk through the steps of what they do when they close up the room when the week end is over........
They shut off the receiver and tv, Then they turn off the lights and close the door.....
BINGO!... The light on the power strip went off....... Turns out the light switch on the wall was the culprit... The light switch turned everything on that wall off...So the receiver did not get any power for a week....
we moved the surge protector to another outlet and I have not heard from that customer for over 6 months now....
Good luck, I hope this has helped you or anyone else having this same issue.