It is sometimes observed that questions of "justice in acquisition" do not much arise any more. However, judges face those questions on a daily basis in courtrooms adjudicating copyright and patent matters. In United States copyright law, for example, an intriguing dilemma regarding derivative works has developed that raises what appears to be a new issue regarding John Locke's sufficiency proviso.
Wendy J. Gordon, Copyright's Derivative Works Doctrine and an Upside-Down Proviso (Mar. 2010) (unpublished manuscript).