I’d argue that embarrassment at hat hair is just as much a convention. In a place where the etiquette is to take off one’s hat, surely hat hair is considered the lesser embarrassment.
That said, I would expect the type of restaurant the OP describes to have a rule about hats if it was expected there, same as I’d expect them to have rules about other clothing–e.g. men must wear a suit and tie. It seems like this place is instead allowing the etiquette to evolve naturally.
I personally suspect the change in hat etiquette is due in large part to the decline of hat wearing in general. Wearing a formal hat (i.e. not a baseball cap or similar) is seen as more formal dress than standard, and thus continuing wearing it is not seen as disrespectful.
The baseball cap, due to its informality, seems to be the exception. It may be left on in informal situations, but still tends to be either removed or not worn in more formal ones.
The other exception is possibly the cowboy hat, which I suspect is just due to how those who wear them are more likely to adhere to older etiquette in general. Though it could possibly also be that people don’t see that cowboy hat as being as formal.
This is nothing new. My Boomer parents taught me plenty of etiquette and table manners, but they never taught me anything about hats, because hats were never a part of their world. Hats are something you wear to keep the sun off your head, nothing more. I wouldn’t wear one indoors because, by definition, there’s no sun indoors.
c’mon. The reason you take your hat off inside is because it drips on your shoulders after you’ve taken your coat off. And because it gets in the way. And because it blocks your sight lines.
I’ll accept that leaving your hat on inside might indicate that you want head protection and might leave suddenly, or might indicate that you consider your contemptible inside location no better than the street, but that’s not “original” – it’s in contrast to the basic norm of taking off your hat and coat when you come inside.
And observe that women, who wear hats inside, traditionally wore small inside hats inside. Not fedoras. They sometimes adopted outside hats (eg, shepherdess hats), but that was a conscious decision – cf “hipsters”.
In the “Cat Who…” books by Lilian Jackson Braun, her big-city reporter Jim Qwilleran has to adjust to Moose County. Where he asks for a recommendation for a good restaurant and is asked “Hats on? Or hats off?”
400 plus nerve racking miles later Qwill and cats arrive in Moose County. The introduction to this new environment does not start off smoothly for Qwill. The rural life is too totally strange to Qwill filled with bizarre customs (hats on or hats off dining), terrifying noises (loons) and even requiring a new wardrobe.
That was from a review of The Cat Who Played Brahms. It comes up a lot, here’s another reference in The Cat Who Sang for the Birds:
“How about Chet’s palace of gastronomy in Kennebeck?”
“I thought you didn’t like barbecue, Qwill.”
“I don’t, but I feel the need to further my education.”
“Okay… at Chet’s anything dressier than a tank top looks pretentious. And be sure to wear a baseball cap. It’s a hats-on dive.”
By the way, it really bothers my mom when she sees anyone wearing any kind of hat in any building, so going out to eat with her in Wisconsin means watching her fume.
She’s in her mid-90s, and also fumes about men who don’t stand up when a woman walks in the room: “They should show her respect!”
“Uh, mom, why is standing up a sign of respect, and wait, why shouldn’t they show men respect?”