I would seriously question whether 17 U.S.C. § 1201(a)(1) is relevant at all. This law is specifically for "Circumvention of copyright protection systems". Does Snapchat own the copyright of pictures distributed using its software? or rather do the users own the copyright? I suspect the answer to this is the latter -- that users own the copyright to the works distributed, and this would render the law irrelevant. Moreover, I would argue that the software protections put in place by Snapchat are for reasons of privacy not for reasons to enforce copyright.