Have you been to south Louisiana? I assure you, around here, hospitality is genuine. Other parts of the south may be snobbish but here, we take pride it making newcomers feel comfortable. At least, that's always how it has been in my family.
As far as ANYONE calling to get money from you. Do not trust anyone, southern or not. It doesn't matter how nice they are. You are much better off researching and giving to a local charity.
I was born and raised in Chicago but have now lived in Louisiana now for 15 years and trust me the "Yes ma'am, No Sir" is definitely not nonsense. The most polite, genuine and polite people reside in the south....especially in SW Louisiana.