Good question. I looked up that part in Vilos' book and it doesn't go into what locked means. It does say that the Federal law was found unconstitutional but congress tried to claim it was matter of interstate commerce... That is another story..
I would think locked means that it takes a key, combination, or fingerprint etc to open. So something that can't just be opened by anyone. Something that only the authorized person can open (with key, combination, biometrics, etc). That is what I think of when I think locked. A case that simply closes and has some latches to hold it closed isn't locked to me.