I'm from NC but lived in CO for a few years and was teased by a co-worker when I used "might could." I have never used it to "gently say" or in any other way say "no." I have always used it in ways such as L Wood suggested or as porsche suggested in that "might" implies something that is not definite, something that is dependent on another set of conditions. A PA co-worker of mine always substituted the word "left" for "let" (allow) which I have heard more than one Pennsylvanian use so I don't think southerners have cornered the market on redundant or poor grammar, regionalism, or idioms. (That's not to pick on folks from PA either. It's just an example.) I wish I always used perfect grammar but am smart enough to know something incorrect is bound to pop out occasionally. Also, if southerners are so stupid, why would northerners EVER want to associate with us and retire in our "neck of the woods"? One of my favorite sayings for a sign says, "I wasn't born here, but I got here as soon as I could." I worked at a southern university and spoke to a mother in New York one day whose son was attending our local university (tuition here at that time for out-of-state students being more affordable than her in-state tuition). She said that he fell in love with our area and had no intention of moving back home. Imagine that! I also realized that my southern accent doesn't deserve to be ridiculed any more than a northern accent or an Irish accent or an English accent. As another responder suggested: let's just enjoy the differences.