You are within your rights to ask to see the radar unit and its within the cops rights not to show it to you. Refusing to consent to a search is not probable cause but the cop can request a warrant if he is really suspicious that youre doing something illegal and then youll get searched anyway. I always make them do the paperwork even when im not hiding anything. Almost all cop cars have video in them, so when you get pulled over and question their methods, they have it on cam. By the time you get pulled over, most cops have dealt with a bunch of aholes that question their authority, so when you ask for the radar numbers or question why they are searching your vehicle ( a cop can search any part of the vehicle they can see without opening anything ) anywho, when you do that to them they get really pissed!! Just some advice: like a lot of people said, RESPECT will go a long way, even if the cop is an ahole. If they perform an illegal search, let them, itll show in court and whatever they find is inadmissable. Stop screwin around, most people dont get pulled over for nothing.