I'm going to call major bullshit on the south argument. I don't care if people say "thank you" "yes ma'am" etc.. that doesn't necessarily denote manners. My experiences in the south is that people are so concerned with what other people are doing instead of themselves that rumors fly with more frequency than the jets at Seymour.
Then of course we have the whole guns, god and government crowd. If someone dares say they don't believe in god or they support a democratic president and they are white.. well that person is just scum and doesn't know how bad they are and they should repent or they'll die in a fiery hell. God doesn't support niggers in office and especially those who aren't really from America to begin with
I see more bigotry and ignorance in the south than other regions and the archaic ideals that pervade the societal boundaries here show more lack of manners than a simple "Yes Ma'am" can cover up.
So personally, I'd much rather have people and children not use thank you and other "manner" identifiers if they would just focus on their own goddamn problems and quit meddling in other people's business. I'd rather some kid say "gimme that" than have to deal with the over abundance of bigotry that resides here in the south. Bigotry certainly lives in other regions, but I can say with full confidence that it's not as rampant as it is in the south.. and I really fail to see how bigotry combined with racism equals a more mannered society.