I don't think its improper to ask for someone to follow common courtesy, in this case- removing one's hat indoors... unless of course if its some religious/cultural thing and in this case, unless you REALLY worship the saints, isn't an issue. This is also true with cases of a diner being asked to remove an offensive article of clothing like a shirt with a swastika on it. my big thing is...this place isn't even a tremendous restaurant that would require such high standards of dress. it's a dimly lit, uppity steakhouse. how would the hat make any difference, whether he were wearing it or not? maybe he doesn't think that it's a big deal. and he is the customer. not sure i'm following you on the comparison to an offensive shirt. it's just a hat.