This article from cdf-info
At a Digital Hollywood panel in U.s, cable companies claimed that they want rewritable DVDs in future set-tops to archive video. However studios are lobbying the network providers to build a security mechanism into the DVD players.
The current scheme under discussion is preventing disks made on a set-top burner from being played on any other system by linking the content to the serial number of the set-top using triple DES encryption.

That's the approach current digital set-tops already use with content stored on their hard disk drives.

However, no one has made a formal proposal for a security mechanism yet, but it is expected that rewritable DVD players will appear in set tops in about a year.
I would like to know as I'm thinking of getting one...
Rw players are already available arent they?
ALso dvd's recorded on one Machine can play back on others ??
Content on players hard drive isnt linked to that one machibne is it??
I would like to know as I am thinking of getting one .....