Is the bluetooth sets produced so that the policeman cannot see you talking while driving?!!?

Answer 1

No

Answer 2

That's an another use of it, also it will make you looks like a mad guy, talking, nodding and walking on the street while your cell phone is kept in your pocket

Answer 3

I'm sure they can still see your lips moving, and not the music. It's because it frees up your other hand to drive and be more in control.