I wasn't raised to use Sir or Ma'am. In fact, unless you are older than 55, I will call you what you introduce yourself as...for example, if one of my mother's friends around her age or younger introduces herself (or is introduced as) Wilma, I will call her "Wilma." If I'm introduced to a grandmother's friend or person who's older than 60, then I'll usually add a Mr./ Ms. onto their first or last name (like "Ms. Gloria").
But then again my family is really informal with names (I usually call my parents by their first names, as does my mother), so I'm not a good example of political correctness in naming conventions.
Finally, a pet peeve: please, when you introduce folks to me, please include the name I am supposed to call them. It would drive me crazy to be introduced to somebody's parents as "mom, this is shelacious, shel, this is my mom." What am I supposed to call her--MOM???
With marriages, and remarriages, I can't assume her last name is the same as yours. If, however, you say, "mom, this is shelacious, shel this is my mother, Mrs. Branford," then I know to call her Mrs. Branford. You would think that is commom sense, but NO.....