HBO is saying that fair use applies only to broadcast, not to cable:

Q:  "Has the law changed? Please help me understand what is (and is not) legal for me to do with HBO programming. I have grown accustomed to making and often sharing copies of programs with friends and family.

The laws on copying distinguish between broadcast and non-broadcast programming. Broadcasters are required to permit consumers to make a single copy of broadcast programming for time shifting purposes. However, the law allows non-broadcast programming networks to decide what copying privileges they wish to extend to consumers."

HBO's position has support in Section. 1201(k)(2) of the DMCA, which says that pay-per-view/subscription television can take advantage of copy control technology required to be part of VCRs.

The interesting question is how subscribers to HBO will feel about this.  Are they so used to making copies that they'll leave HBO in droves?   Will they generally abandon cable for online sources of content?  Probably not. 

More from HBO's FAQ:

"Q:  Is only HBO doing this, and why?

HBO has decided to begin implementing copyright protection technologies now with the increasing proliferation of digital consumer electronic equipment. As television transitions from analog to digital technology, it will become important for distributors of high value programming to take similar steps."

Hang on to your old open devices. And don't look to cable and satellite providers to provide you with lots of choices.  Bit by bit, the analog hole is going to close.