Thank you iFly, I take it this is the same if you are turning right or straight? That was the other point that came up as well.
I'll tell my friend I was right though .

Recently driving with a friend when following scenario happens: Car a is recently stopped at East-West road. Facing west (so on our right) Car b in front of us, north bound on through way ( no stop sign) Car c us, also north bound Car b goes to turn right (east). We car c have our signal on to go left (west). Car b is about half way through their turn (so blocking view of car a). We start our left turn. Car a then tries to turn left (south) in front of us. Since we were turning, we weren't going fast. My friend straightens out and gives the guy (car a) a honk (who also stopped in middle of his...