Is it ethical to use this form of deception? Many shopkeepers use fake camera look-alikes, and other decoys. It is ethical and reasonable for individuals to do the same during the times when they are under surveillance.
Make some extra darkglass objects and give them as gifts. Give a friend the gift of symmetry. I'd be delighted if someone gave me a darkglass ball with a little antenna sticking out of it. I'd carry it to the MIT bookstore when I was purchasing my course textbooks. The manager would ask me what it was, and I'd be able to say, in all honesty: "I don't know what it is; someone gave it to me... but come to think of it, it looks an awful lot like the dark spheres you have hanging from the ceiling... what are those dark spheres you guys have hanging from the ceiling?... maybe if you tell me what they are it will give me some clue as to what might be inside this ball".