Eh, we don't know if the car was forced to stop because of a jumpy group or what. Arguing over events we were not there to witness is useless at best. I have seen cyclists not even slow down to take a left at a light while the cars coming in the opposite direction brake like mad to keep the cyclist from meeting Darwin in the afterlife. Who knows. No matter how many wheels they have under them, you can count on stupidity coming up everywhere.