There's no given definition that I could find of the word "exposed." Presumably you're taking it to mean "expose to air" versus "expose to view". The common definition of the word expose means to make visible. The only support I could find for your claim is in CA PC 313.1(d) where "exposed to view" is used. Everywhere else only the word "expose" is used. If you look at the other uses of the word, you'd have a tough time arguing that expose means, "expose to air."
Creative argument, but I wouldn't use it except as a last-ditch effort to argue my way out of something. I certainly wouldn't rely on it as my sole defense.