i dont think they can do that. correct me if im wrong. maybe if the cop wanted to be a dick, yes. but my dad has been in our driveway countless time changing oil or something along those lines with a beer and the cop who normally patrols our neighborhood has actually stopped just to see whats going on and never said anything about the alcohol or anything. and if youre blowing above a .08 you shouldnt be working on a car anyway.