So this isn’t actually a scenario directed at me, but my girlfriend recently told me that her dad was really tempted to tell a group of strangers at a restaurant to take their hats off while they eat. He’s a very traditional type of guy, and so he was very angry to see that they (random strangers) were eating with their hats on.  When she told me this, I was kind of taken aback, because to me, it’s none of his business. I’m asking because maybe I’m missing some restaurant etiquette? 