Under US copyright law, we have something called the "first sale doctrine."
Notwithstanding the provisions of section 106(3), the owner of a particular copy or phonorecord lawfully made under this title, or any person authorized by such owner, is entitled, without the authority of the copyright owner, to sell or otherwise dispose of the possession of that copy or phonorecord.
17 U.S.C. § 109(a). In practice, this means that once one lawfully obtains a copy of say, a DVD of Gigli, one is free to sell or give that copy to a third party without paying anything to the copyright holder. (In that particular instance, I can't imagine why such a payment wouldn't be part of a scheme to defraud, but that's for another time.) This applies in a twisted sort of way to HBO's situation (twisted, as we'll see later, by the telephone book). Once one legitimately pays HBO its license fee for the broadcast, HBO has no right to control what was done with the copy one receives.
On the one hand, that "copy one receives" is the issue here. Under a strictly formalistic view, a copy made on a digital recorder is not the copy one receives from HBO; it is a copy of a copy, and arguably falls outside of § 109. Of course, the problem with such formalism is that what one receives over-the-air, or through-the-cable, is also subject to the same problem, unless one somehow goes Neuromancer and has it jacked directly into one's head in electronic form. Instead, one must rely upon multiple coding "black boxes" between the "true original" and the perceivable copy. HBO's position—which is neither entirely consistent with nor entirely inconsistent with Sony-Betamax—is that a digital copy saved "for later" is too far from its "original."
Of course, HBO doesn't reach this position by relying on copyright law. It does so by relying on the phone book; or, rather, a shrink-wrap license for a CD-ROM version of the phone book that was held enforceable, despite the noncopyrightability of the underlying material. This is the notorious ProCD v. Zeidenburg case, which is a post-Feist decision out of the Seventh Circuit (Easterbrook, J.). In ProCD, a shrinkwrap license agreement prevented purchasers of the CD-ROM version of white pages for a large portion of the country from putting the database online for others to use. This is the closest we've got to what HBO proposes to do: By combining a restrictive licensing agreement with chapter 12 of the Copyright Act (the evil anticircumvention provisions), it hopes to reach the same result.
On the one hand, I have a bit more sympathy for the kind of material that HBO wants to protect: Material that is clearly protected by copyright, and is subject to piracy. On the other hand, this does mark significant overreaching on HBO's part, and probably constitutes an unfair trade practice. If, that is, anybody actually paid any attention to that sort of thing any more. Given that HBO is itself a studio… and owns the equivalent of its own chain of movie theaters… students of antitrust law will know the line of cases to which I'm referring, which forced the studios to sell off their movie theaters as restraints on trade. I see this as more a problem of who owns and controls the copyrights in question than with copyright itself. One set of interested parties has been allowed to take collective action, while all other sets are prohibited from doing so. I'm saving the details for scholarly work, as they're much, much too complex to explicate in a blawg. My conclusion, though, is not: Patronage is inconsistent with the Constitution and the Copyright Act, and cannot be excused through the use of common-law evasions.
There. Is that clear enough?
Historically, the only way to effectively combat piracy has been by offering high-quality products in a convenient package through wide distribution at a price insufficiently greater than the so-called "generic equivalent" to justify the end-user's inconvenience in seeking out the "bargain." All of this assumes that copyrightable works are in some fashion fungible, which at the margin is simply not true. Again, though, the reasoning and evidence behind that is just too complex for a blawg.
All of which is far too difficult to plow through any longer given my present low blood-caffeine level (less than 1.5%).