Are Creative Commons licenses enforceable in court?  Yes. In an important decision titled Drauglis v. Kappa Map Group, LLC, 128 F. Supp.3d 46 (D.D.C. 2015), Judge Amy Berman Jackson of the United States District Court for the District of Columbia has issued a decision that: 1) confirms the enforceability of Creative Commons licenses under U.S. copyright law; 2) interprets the attribution requirement in the licenses to have the flexibility that is consistent with the licenses’ language and intent; 3) holds that incorporating a photo into the cover of a road atlas creates a collective work rather than derivative work under U.S. copyright law; and 4) holds that the “ShareAlike” condition in the 2.0 version of CC licenses is only triggered when a user distributes a derivative work as that concept is understood under U.S. law. The court also rejected some misdirected arguments about copyright management information under Section 1202 of the Copyright Act. 
http://us.creativecommons.org/archives/1152