It is very admirable that Southern Gentlemen still open the doors for ladies. As a Northern transplant who has lived in the South for at least 20 years, I can certainly attest that the men here are very polite.
But, I would like to also say that Northern men are very admirable in their own right. Where I grew up, men were not very polite; they were blunt and honest. They spoke their minds and they did what it took, no matter what the sacrifice. One September, a great many of these Yankee men rushed to the scene of a calamity, and not thinking of anything else than saving lives, rushed into two burning skyscrapers. Many of them lost their lives; many more who stayed around for weeks, searching for remains of loved ones, have sickened and died.
A code of ethics can involve opening doors for ladies, which is lovely. It can also involve being more incredibly heroic than any of us can imagine.