This is something I never do because I don't feel like it is safe for me . Someone else might be perfectly comfortable doing it though.
Today in the afternoon, I was following a Silver/Black 954RR all the way down Cambie from 41st all the way to 12th. At 12th, he/she was signalling to turn left, but instead of waiting behind the row of cars, the rider decides to creep up along the right side of the cars and when the light turned amber/red, the rider turned left with the car that was already in the intersection.
I was really surprised to see this, because even though I've seen a lot of bicycles do this (something I don't agree with...), I've never seen a motorcycle rider share a left-turn lane with a car before.
What's your opinon on it ?