Yes, I know my manners. (See my "please?") And I know that "Mrs." is the polite form of address for married women.
Here's the thing: Unless you've met the woman’s spouse, why do you assume she's married? And even if you've solid reason to believe she's married (perhaps she’s mentioned a husband, for example), how are you to know she took his last name?
Seems like you're just inviting an awkward situation, sending e-mail or letters addressed "Mrs."
I received an e-mail addressed to "Mrs. Farnsworth" a couple weeks ago. (Hence this topic.) I get that this person, who's still in college, is trying to be respectful of someone who holds a more established position. (This is all seeming so formal. And it's making me feel old.) I've never been offended by someone addressing me simply as "Leslie," but I get that maybe some people would be.
My grandmother, Gladys Farnsworth, bought me the 14th edition of Emily Post's Etiquette: A Guide to Modern Manners when I was in junior high. She was even formal enough to inscribe it "Grandmother Farnsworth," even though my brother and cousins all called her "G. G." (See below. Imagine! Back in her day, they taught kids something called "penmanship.")
I consulted G. G.'s gift for guidance on this issue, and it wasn't helpful. Maybe more modern editions give different guidance. The book believes all women should be identified as "Miss" or "Mrs." unless they are living with an unrelated man to whom they are not married. (Horrors.) Even widows and divorced women are "Mrs." (That was a new one to me.)
Sorry, Emily Post, I disagree. I'd rather be seen as a person, her own creature, completely independent of her marital status. I'm not married and never have been married, but I don't want to be a "Miss." And if I had been married and were now divorced, I wouldn't want to be a "Mrs." I don't particularly like the hard, buzzy sound of "Ms.," but if I can't be addressed as just "Leslie" or "Leslie Farnsworth," I'll take the marital-neutral form any day.
What should I have said to the hapless student who sent an e-mail to "Mrs. Farnsworth?" Something flippant? "Sorry, my mother's e-mail address is firstname.lastname@example.org." Something overly earnest that would have made us both uncomfortable? "Oh, I'm sorry, I haven't yet found the man I wanted to marry." Or something that raised more questions? "Just call me 'Ms.,' kiddo."
I was pretty annoyed to be reminded that women are identified--unlike men--by marital status, more than impressed by his attempt at respect. The form of address exasperated me and made me think him myopic and immature. His attempt at politeness backfired. It made me uncomfortable, and manners are all about making everyone involved feel comfortable.
So how did I respond? I answered his questions, agreed to meet with him for an informational interview, and signed the e-mail "Leslie." Someone else will have to guide him.