I'm not 100% sure. I just perused my 2006 Rulebook & I didn't see it in there... but I can tell you anything you want to know about decal placement. Ha Ha Ha
If memory serves me right, and it doesn't always so I may be wrong, a driver loses 20 points for an oildown but can earn freebies for a certain number of oil free passes (don't recall the number). I'm fairly certain that John, Ron & Robert are all safe (freebies in the bag) but again, I'm not 100% sure.
Great question though, given the desire for some to earn 20 points for setting a national record - could be a wash if oil is involved...