2 shot penalty because his club happened to hit a leaf on the backswing? Bullshiiit. The "rules" were never intended to apply such a penalty for something like this. It would have never been assessed on Tiger Woods, Phil Mickelson, etc..
would have been assessed to every single person that was caught on camera...actually, petterson should feel bad that he didnt know the rule enough to call the penalty on himself...its really cut and dry, to be honest with you