I wore a backwards ballcap in the late 70's. Of course, I was working as a welder, at the time. The bill of the cap kept hot sparks, and slag, from going down the back of my shirt collar. That was a little trick that I learned from my dad. Who would've guessed that we were trendsetters?
Of course, when we were finished welding, and took off our hoods, we would turn our caps around to face the right way.