In looking up available defensive shooting classes, I've noticed that a couple of them advised students to wear a ball cap. Just noticed the same thing in the rules for one of the indoor ranges. Advised; not necessarily required.
Is that to protect you from your neighbor's brass? Or to shield yourself from glare?
Or is it so everyone looks like a team out there, as per the principles of Rex Kwan Do?
Coincidentally, I have recently become convert to the cult of the ball cap. Never wore them before, except for occasionally sporting a MAGA hat. I've started wearing camo ball caps now, though. (And, no, I'm not going bald, or getting thin.)