Driving in to work today I saw a groundskeeper with a bandana around his neck, the sort you’d use to cover your mouth and nose if you were using a lawnmower and didn’t want to breathe grass clipping. It made me think of gun-toting people who want to keep their identities secret, like terrorists attacking Jerusalem and such, and how humans recognize each other by our faces.
But what if we encountered an alien race where the front-parts of their heads were pretty uniform and the identifying features — horns, birthmarks, fur patterns, Klingon cranial ridges, and so on — were on the top of the head? Perhaps some sort of insect race where the front is all mandibles and eyes, and the top of the head is where all of the recognizeable bits are. These creatures would hide their identities by wearing hats, and perhaps their fashionable headwear would be front-applied items like bandanas.
And if they came to Earth, would these aliens immediately consider us dangerous and untrustworthy, because the human race wears hats (on the top of our head), which the aliens consider an method used by people trying to remain anonymous in order to perform criminal acts?