Look I, nor you was there.
1) "becomes aware that the driver of another motor vehicle intends to overtake"
2) "visible signal by means of flashing the headlights"
-- Was he Aware? The report says the cop flashed him.. did he see it, I don't know neither do you?
If not, then he was not aware!!one!11!
1) "first vehicle shall steer that vehicle to a lane to the left of the one in which he or she is driving, without endangering himself or herself or other traffic or property on the freeway"
-- Again, was it safe? Was there another car flying up on the left hand lane? Was there even slower moving traffic? Motorbikes lane splitting?? So was it safe, I don't know neither do you?!!one!11!
EDIT: A Judge has ruled on this matter, as well the motorist was in the right and the cop in the wrong. I'm sure the judge knows the law and case law better than you or I. So it's already been settled, no reason arguing actually.