Wendy Gordon is the Philip S. Beck Professor of Law, Boston University School of Law, and is currently serving as the Bacon-Kilkenny Distinguished Visiting Professor of Law at Fordham University School of Law.
Now that Apple is removing DRM from its itunes songs, newspapers are trumpeting the move in ways like this: "COPY AN ITUNES SONG? GO AHEAD, APPLE SAYS."
The copyright purist that lurks in me has the urge to remind the news-writers that removing DRM doesn't also remove copyright's legal restraints. But then.... if no one corrects the error, and the public begins assuming that an absence of DRM amounts to a permission to copy.... and if the record companies don't correct the prevalent error... then music copyists will get a defense of IMPLIED CONSENT wherever DRM is absent from a song they've purchased.
If so, that in turn would make the newspapers' overstatement true. It would also make what too often is custom's vicious circle, into a virtuous one.
In addition, maybe the implied-consent defense (in the form perhaps of a quasi-estoppel argument) would even extend to people who copy recordings they didn't initially purchase. After all, it's not crazy for people to think that copyright owners could consent to what's sometimes called 'piracy' and sometimes called 'sharing'. Un-negotiated copying can serve the copyright owner's self-interest in many circumstances, as Ariel Katz, Mike Meurer, Doug Lichtman and others have reminded us.
Of course, the newspapers aren't the only ones doing the work of turning custom's wheel toward the public's direction. See, e.g., Best Standards project of Peter Jaszi and Pat Aufderheide, now joined also by Lewis Hyde and others.
For more on consent and copyright, see e.g., Jennifer Rothman's piece, "The Questionable Use of Custom in Intellectual Property" in 93 Virginia L Rev 1899 (2007) and Jim Gibson's "Risk Aversion and Rights Accretion in Intellectual Property Law", 116 Yale L J 882 (2007); you might also see my reply to Jim in "The 'Why' of Markets: Fair Use and Circularity", 116 YALE L.J. POCKET PART 358 (2007). For the Katz piece, it appears as "A Network Effects Perspective on Software Piracy" at 55 University of Toronto Law Journal 155 (2005); Giuseppina D'Agostino, has published various pieces on consent in freelance publishing, such as "Freelance Authors for Free: Globalisation of Publishing, Convergence of Copyright Contracts and Divergence of Judicial Reasoning" in F Macmillan (ed) New Directions in Copyright (Edward Elgar Cheltenham 2005) and "Canada's Robertson Ruling: Any Practical Significance for the Copyright Treatment of Freelance Authors?"  2 EIPR 66. For Mike Meurer, Doug Lichtman and others, see the literature on price discrimination: if works are shared, they become more valuable, and a person who intends to share a copy she purchases will be willing (under certain circumstances) to pay more for it.