To correct Eric, what he said about the contracts is in no way confirmed from everything I have gathered over the years. In fact, cable stations have sold me equipment and Mediacom just gave an employee an old 4000...
As for plugging it in and getting forecasts... the answer is "yes" but "no". Yes for the XL, mine is still chugging along cuing a D or M flavor on the 8s... mostly D. This has taken some reverse engineering and three brains. Older legacy units... answer is still yes but with all of my reverse engineering efforts, I haven't been able to make much progress as the equipment I would need comes with a hefty price tag. Due to that, my II, III, and Junior sit in storage.
Now, would Comcast give an IntelliStar away? Doubtful. I'm sure that TWC requests them back if there is faulty hardware, and given it's still the most heavily used system in the field today there isn't a great chance of these machines sitting in an old equipment closet. Give it five more years when the IS starts to be replaced by the IS 2 Jr (if that happens...).
For those who say it's not possible for an XL to run without AMC 11... check out my youtube. I upload videos quite often.
https://www.youtube.com/channel/UC9XWVJjbCUzImvznI1sHSpw