My opinion is NO...it isn't OK to wear a hat in any restaurant. And @the " Sharon "
Whether it is considered Casual.Fine Dining, Casual Dining or just going out to Dinner. Going to a typical diner is different sitting at a counter for example. It is usually typical of the customers..hey it's a Diner.
I have on every occasion that we have been to the Sharon some men show up in Shorts, T-Shirt, complete with the Baseball Cap and yes with the hat placed on the dome " Backwards ".. like their head is on backwards, complete with the sweat mark(s).
Meanwhile the Lady that is being escorted looks like a million $$$ Dollars . Happens all the time.
I think it is classless and shows a serious lack of manners.
Look men leave the Cap/Hat in the Garage and show some class rather than lack of it.