said by The Q:
...Otherwise I could just swap my hard drive with yours to share shows. Great for you and I but not so great for the person/company that actually owns the content or copyright.
Not what I said. I wouldn't think that an external HD has to be all or nothing - either it works with all DVR's, or it works with none at all. Whyc can't it work with JUST one?
When an external HD is first formatted, Comcast (or any provider) should be able to specify a unique ID code the DVR embeds in the HD, which Comcast then assosicates with that DVR. If you switch DVR's, Comcast can then updates it's database, with the new DVR asking the headend, "Am I authorized to access recordings on HD xxxxx?" If yes, it works, if not, it doesn't.
Now, if that's deemed to be too insecure, such that hackers could crack it, and access recorded media, that might be a valid reason.