I had the misfortune of watching a friend get right hooked last night, and he is 100% ok, nothing more than bouncing off the car and a scratched up brake handle. He didn't want to go to the hospital and felt sort of bad for the driver. The new Prius that hooked him has a nice hip sized dent and some "racing stripes" down the passenger side.

But what happened was we were coming up to a light that had just changed from red to green where the driver was waiting. However the driver was sitting a bit to the right, there are no marked lanes here persay, but the intersection is setup where a car sits to the left of the lane to allow for busses and people turning right to come alongside them, he was straddling that invisible line.

My friend was out in front of me and we hit the intersection rolling so he came along the right side of the car; I was a little leery about following so I backed off a bit and signaled to take the lane fully and come behind the car. Well sure enough the driver turned right into a parking lot with no open businesses and my buddy rode into his door and fell over.

We stopped, the driver pulled the "I didn't see you" and we explained he didn't use a turn signal, he wasn't paying attention, and so forth. My friend didn't want to call the cops because he didn't want to deal the Chicago PD (they are a pain), he kept an even temper despite the raised voice and told the driver he has to pay attention and signal his turns. This area is flooded with cyclists, they even take up car parking spots (the city that is) to allow for more bike parking in the street.

My question is:
Should I have given a verbal heads up to my friend that the driver was favoring the right side and MAY turn? I know I am not the keeper of my fellow man, and maybe I have some internal Spidey Sense that made me think of it, but I want to be safe AS WELL AS keep other cyclists safe.

And for those who haven't watched this before, it isn't fun to watch. Little nerve wracking.