Greplaw has a post asking if the DVD CSS can really be considered copy protection, since making an exact copy of a DVD is totally possible without knowing the encryption method. The copy will then have to be read in a normal DVD player like the original.

The original question is here and there is an answer by Edward Felten who does address the strategic advantages to rely on a trade secret protected method to control distribution of players.

I must assume that some people must have thought of the ambiguous nature of CSS before since the DMCA uses the words « technological measure that effectively controls access to a work » rather that make any reference to the copying process.

The WIPO copyright treaty originally used  » circumvention of effective technological measures that are used by authors in connection with the exercise of their rights under this Treaty or the Berne Convention and that restrict acts, in respect of their works, which are not authorized by the authors concerned or permitted by law« 

Through this wording, laws worded like the DMCA grant protection and status to any trade secret, which in traditional IP laws are not subject to any particular protection. It’s that broad delegation, that blank check to a method yet to be determined, that bothers me a lot in with the DVD issue.