WChop,
Keep in mind that there is only one state that allows split-laning--that being CA. Up to 35mph and no shoulder driving.
When you are driving in that state, on a bike, it is an awesome advantage to have. As to scratching somebody's car--in practice, most drivers(even big rigs) will give you some extra room if it is tight. Yes, there are a lot of good awake drivers out there. The asleep, don't look in their mirrors and the Dbags will actually put the squeeze on you--Where do you fit in the picture WChop. Besides opening the door on some biker could actually kill them--hardly proportional to a little scratch or even a mirror.
Opto