My device name is a invisible special character, it doesn't show up anything. But i still don't feel confortable leaving my Bluetooth ON all the time when i'm not using it (e.g. for listening to music or connect my mouse/keyboard).
Discussion
Having a special character is even worst for your privacy. If you use a device name nobody uses, it can easily be spotted anywhere in the word. "John Doe's Macbook Pro" is a way better privacy wise name for your device (not the best one)