I completely agree, I've seen no dings on autopilot at and I have experimented quite a bit over the last 6 days after having a terrible first day score.
After some careful experimenting, I have noticed that if I follow and break even more carefully than the way autopilot does I'll get dinged for following too close and aggressive breaking when approaching stop lights, even though I'm being much more smooth and subtle that AP does. Also, I have noticed on a very short freeway test, I was in Autopilot following a car on 1 car length for 5-10 minutes, got no dings after a quick stop/exiting the car and checking the score. Then, I did the exact same thing, but then turned off Autopilot for a mile and kept the same or slightly longer distance than AP - and I got dinged for following too closely.
I then drove straight through the town, 10-20 stop lights and let Autopilot do everything, with crazy aggressive following and stops at times, and one crazy fast curve it took without slowing down the way it should have - but I DIDN'T have to intervene so I didn't. Perfect score! If I'd driven like that (based on first day of driving much better than AP) my score would have been all dings for all categories.
Kind of crazy game to be