Good question, someone should ask Sparkfun what they think.
However, I am fairly sure under Copyright law that a 3D model of a utility object is not a copyrightable thing. In general, copyright applies to creative or artistic works, and "utility articles" are specifically exempted. For example, this is why it is difficult to get copyright protection for clothing or costumes, even if they have a creative element, in whole clothing is considered a useful article.
Actually, it is also arguable whether an image of a switch is copyrightable, since there is so little creative element, which would make the CC license inapplicable.
Unfortunately, in all cases of infringement, a court must decide on issues of creativity, there is no blanket rule pre-applied (ie. there is no law saying pictures of switches for retail purposes are not copyrightable, or that pictures of dragons are copyrightable).
I'm also fairly sure that if someone thinks they are threatened by competition, they will create a claim under copyright, trademark, trade secret, even if it is totally bogus but have a large legal budget. DMCA makes it fairly easy for people to issue takedowns to make life awkward, there is a right of reply but still going through the paperwork is tedious.
I was only able to find one case relating specifically to copyright of 3D engineering data, where the object was not an artistic one. Michael Weinberg is an expert on this stuff, he wrote an article on the CanadaDrones suit http://makezine.com/2014/06/25/us-legal-lessons-from-canadas-first-stl-ip-infringement-case/ Weinberg concludes that the suit was probably not likely to succeed, but was settled out of court, so we don't have a court opinion.