Potentially interesting article: "Secrets Revealed: How Magicians Protect Intellectual Property without Law". Here's the abstract:

Intellectual property scholars have begun to explore the curious dynamics of IP's negative spaces, areas in which IP law offers scant protection for innovators, but where innovation nevertheless seems to thrive. Such negative spaces pose a puzzle for the traditional theory of IP, which holds that IP law is necessary to create incentives for innovation.

This paper presents a study of one such negative space which has so far garnered some curiosity but little sustained attention - the world of performing magicians. This paper argues that idiosyncratic dynamics among magicians make traditional copyright, patent, and trade secret law ill-suited to protecting magicians' most valuable intellectual property. Yet, the paper further argues that the magic community has developed its own set of unique IP norms which effectively operate in law's absence. The paper details the structure of these informal norms that protect the creation, dissemination, and performance of magic tricks. The paper also discusses broader implications for IP theory, suggesting that a norm-based approach may offer a promising explanation for the puzzling persistence of some of IP's negative spaces.

(Via Marginal Revolution.)