Indians and Chinese in Camrys do this all the time where I live, and for those who think that's in some way offensive, understand that I make a point of checking who the knob behind the wheel is. I subscribe to the same mantra; if you lane swap with minimal distance between you and the car behind, you should be pushing it way harder than them or at least get to speed asap. People who lane swap and then slow down need to be prodded with a stick.
^ this is why i have a heap of odd nuts and bolts in my door card - if yelling profanities out the window doesn't work (with no kids around or in the car) i reach down and grab one and peg it at them... works every time trust me.
i flick 5 cent coins at them
its small enough to not see
but makes a hell of alot of noise when it hits there car