Well, in New Jersey this time of year it's acorn dropping time. This year they are really big. I washed my Prius C this morning and noticed a lot of small acorn ding (dent). I wonder what gauge steel is used on the Prius C top. Did not see any problems with the hood. Been driving in this area for 50 years this is my first acorn ding.
The auto industry may have to react to this. I've been to other automobile websites, and more and more people complain about how easily their vehicle is dented. This isn't a Prius Only problem, as automakers strive to improve fuel efficiency by lessening weight. Just read a thread at a different site, with a different "New" vehicle where the owner was complaining about denting the door frame by just leaning on it while washing the vehicle. I think the best approach is to NOT expect a great deal of anti-dent from your vehicle and try to avoid acorns or other falling objects. It sucks, but I think it's the nature of todays lighter but more efficient vehicles.
I guess you are right, I take a positive view - thinner body metal translates to less weight and that translates to better milage. Just have to remember to park the car in the garage in the fall.
The prius c body panels are thin as aluminum foil. You can dent it just by knocking on it with a knuckle
We got coconuts... and, believe or not, a couple years ago we had hail in one or two areas of Oahu - quite a few people got the "golf ball" look - mentioned by Beauregard - on their cars.