From Southern Ladies and Gentlemen by Florence King:

“Neither can Aunt Pittypat remember that Richmond is 703 and Charlotte is 704, though this usually works out quite nicely, thanks to the Southern Wrong Number Syndrome: If one talkative Southerner dials a wrong number and gets another talkative Southerner, it may well be the start of a friendship. When I lived in Raleigh, I got a wrong number from a Silly Old Maid in Charleston, who after ascertaining that I was not her party, began to list all the people in Raleigh she knew. It just so happened that I knew one of them, too, and we had old home week for twenty minutes. As we hung up, we both said simultaneously: “It certainly has been nice talkin’ to you. You come see me, you hear?”