Falling acorns from oak trees cause slight dents that are visible when viewed at the right angle. I have 2 or 3 in the roof and trunk deck.

I have dents in the trunk and on the roof of my 2007 accord from acorns off my oak trees. So in the fall I have to avoid parking or driving under oak trees. You can see them fairly easy when viewing across the surface like when checking to see if your wax is completely buffed out. Something as as small as an acorn should never dent the surface it needs to be of a heavier gauge or higher strength. This is just a cheap design flaw.