Originally Posted by mister deliberate
I'd say that it's fine if you want to hit the turn lane early, before it's even a turn lane, but you're rude if you do that and then pass the guy on your right who may be waiting to legally enter the turn lane. Usually he will have to wait for you and enter the lane late, at a higher speed than he would like, or he may have to miss the turn. He's not going to put on the brakes while he's still in the traffic lane (if he's a responsible driver or rider), so you're kind of forcing his hand unless you give him a chance to get in.
People around here don't wait in the through lane until they get down to the "entrance" to the left turn lane. They merge over as needed so as not to block traffic in the through lane, which is the reason left turn lanes were put there in the first place.