Brent Sordyl's blog

Yet Loshin, and apparently most magicians, think that patent and trade secret are a poor fit. There are basically three reasons for this. First, part of the value of a trick is that the audience can’t figure out how it’s done; but a patent must explain the details of the invention. Second, tricks are subject to “reverse engineering” by rival magicians who watch the trick done, repeatedly, from different parts of the audience, then do experiments to try to replicate it; and of course trade secrets are not protected against reverse engineering. Third, there’s a sort of guild mentality among magicians, holding that knowledge can be shared within the profession but must not be shared with the public. This guild mentality can’t easily be implemented within current law – a trade secret must be carefully protected, and so cannot be passed around casually within a loosely defined “community”.
(Link: Intellectual Property and Magicians | Freedom to Tinker)