If I am to busy I give one flash of the lights but for cops I would give multiple flashes. sometimes you meet the odd guy and you think is he a cop. usually they flash like mad and wave for you to slow down even when the road is clear and there is no speed traps. one thing that annoys me is the cars that flash like mad when you pass them even when you are well within the speed limit.I have to admit I did see red once on a driver that flashed me then my wee brother.I stopped at the next junction and got off to go ask him what his problem was.
O Yeh.....Seems I have lost the ability to read as well as walk properly. Now what did I do with my reading card.
i always nod, even if you feel like a right plank when they dont nod back. Mind you i went past a whole pack of gixxers a few weeks ago (50 or 60 bikes) and had a sore neck afterward.... Keep nodding, its what sets us apart from other road users!!!