DEAR MISS MANNERS: My fiance just got an invitation in only his name to the wedding of his childhood friend. This couple is well aware of our relationship status, as they visited our city twice in the past year and stayed in our home.

I think he should just attend the wedding on his own, since my understanding is that an invitation covers only the named individuals, period. But my fiance says that a lot of people probably don't know that "arbitrary rule" (his words, which are making me dread the RSVP process when we send out invitations for our own wedding) -- and that the right thing to do is double-check with the bride and groom to spare them the embarrassment of accidentally excluding me.

Can you please guide us in the correct course of action?

GENTLE READER: The prudent course would be to enlighten your fiance before -- as you fear -- his like-minded friends begin distributing their own invitations to your wedding.

First lesson: Rules that are arbitrary may be nonetheless crucial. Whether we drive on the right or left side of the road is arbitrary, but it is crucial to obey the prevailing rule.

Second lesson: That the hosts, not the guests, do the inviting is not arbitrary. Presumably, they know whom they want and have planned for the number of those who have accepted. Even if they do a bad job of it -- and it is indeed rude to invite only half of an established couple -- they should not simply be overridden.

But of course Miss Manners will help you do just that.

Your fiance should say to his childhood friend that he knows the wedding is small, but wonders whether they intended to have room for you. If the answer focuses on the wedding size, it means no, and your fiance may or may not want to attend alone. However, if it was indeed an oversight, this should clear that up.

DEAR MISS MANNERS: I think it is so ugly to hold up your pinky while drinking tea. Do you consider it good or bad manners?

GENTLE READER: It has been both in its day, as Miss Manners recalls.

When tea was first imported to England from China, it was wildly expensive and kept locked up. It was drunk from Chinese cups, which are very thin and, for reasons best known to the designers, have no handles. Therefore, tea drinkers held the cups with as few fingers as possible to minimize scorching, especially of the pinky, which is apt to have fewer callouses than the others and thus be more sensitive.

Because it was a luxury of the rich, that gesture came to be associated with them, and not in a nice way.

As we now have our own teacups with handles, the once-practical gesture is absurd, and only the association with wealth and, by implication, snobbery, persist.

DEAR MISS MANNERS: My friend, who I dated a couple of times, asked me to be his valentine (I received a card and gifts). I accepted. Now, what should I do?

GENTLE READER: How about reciprocating by sending a valentine? And doing whatever the two of you decide, as long as you promise not to tell Miss Manners.

(Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, dearmissmanners@gmail.com; or through postal mail to Miss Manners, Universal Uclick, 1130 Walnut St., Kansas City, MO 64106.)

DEAR MISS MANNERS: I've been pleasantly surprised with how strangers have treated me during both of my pregnancies. They open doors, carry groceries, offer well wishes -- this list goes on and on.

The issue is that as soon as I've had the baby and am wrestling with the baby carrier, diaper bag, stroller and everything else that goes along with an infant, people act like I don't exist and they don't see me. I'm often struggling to just get through doors as people whiz by without a second glance.

Although I don't think there is any formal etiquette surrounding this situation, please remind your readers that moms need the most support, assistance and often patience after the baby is born, and they are trying to muddle through errands after they've finally made it out of the house.

I am not under any illusion that strangers owe me anything because I'm struggling with all of my baby gear, but the difference in how I was treated when pregnant and then with an infant has always puzzled me.

GENTLE READER: Why is it that the prospect of a new life seems ever more enchanting then the life itself?

Miss Manners is pleased to hear that you were treated well during your pregnancies -- and if the same people who showed you empathy don't understand what comes next, then she needs to have a talk with them not only about manners, but also about biology.

DEAR MISS MANNERS: I've always thought that if a man asks for my phone number in order to schedule a romantic date, it is polite for me to give it.

Some of my friends argue that I should never give my number to a man with whom I am not already acquainted, given that he might be a suspicious character who could misuse the number to harass me or derive compromising information from my smartphone.

My thinking is that any man, whether I know him or not, could be dangerous and that, rather than withholding my phone number (something I believe to be rude), I should continue communication, but act intelligently with a sharp eye for suspicious behavior.

Perhaps Miss Manners can help us understand if and how safety changes the dynamic of the situation.

GENTLE READER: And if these gentlemen asked for your wallet, would you feel it only polite to give it to them as well?

Miss Manners assures you that there is no etiquette rule that decrees one must give out personal information to anyone who asks.

While it is true that anyone could do anything, regardless of how well you know them, you are not tipping the hand in your favor. Erring on the side of safety -- provided that you decline all reasonable requests politely -- is always correct. So is giving your work number to a gentleman who interests you.

DEAR MISS MANNERS: I have a 10-year-old son who hates to write thank-you notes. How can I desensitize my ears to his complaining?

GENTLE READER: Or you could sensitize him, instead, to the relationship between generosity and gratitude. Miss Manners suggests your offering to explain to his relatives that he finds receiving presents to be too much of a responsibility.

(Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, dearmissmanners@gmail.com; or through postal mail to Miss Manners, Universal Uclick, 1130 Walnut St., Kansas City, MO 64106.)

DEAR MISS MANNERS: We are having a party for our employees and want to be sure we are politically correct with our invitations. We want to invite employees and their spouses or significant others (girls of girls and boys of boys). How do I word this invitation to accommodate our lesbian and gay employees?

GENTLE READER: Although Miss Manners lauds your desire to make everyone feel welcome, you have made her realize that trying too obviously hard to be inoffensive is, in itself, somewhat offensive. Instead of researching all possible personal ties your employees may have, you could use one simple word: "guest." Tell them that you would welcome each of them bringing one guest to the party. Or that each invitation is for two people.

DEAR MISS MANNERS: What is the proper etiquette when receiving a gift one already possesses?

I took a good friend to lunch for her birthday and gave her a gift, a book which was absolutely perfect for her. It was so perfect, unfortunately, that she already had a copy of it.

I asked if she would like to take it back to the bookstore and exchange it for a book of her choice. She then slid it across the table and said that she knew I could choose something else she might like. I have again purchased a book, which I hope she would like and does not have.

My own response would be not to mention that I already had it, to exclaim how perfect the choice was, and then either to give the book to someone else who might enjoy it or to make the exchange myself.

GENTLE READER: Your own response is the polite one. When someone has tried to please you, it is rude, as well as disheartening, to respond by announcing that the effort was a failure and the would-be donor should go back and try again.

Had Miss Manners been in your position, she would have slid the book right back and said, "Oh, I'd probably just make another mistake. Just dispose of this in whatever way is easiest."

DEAR MISS MANNERS: What do you make of people who ignore a friend's urgent texts or emails for several days, but can be seen by that friend simultaneously, and at length, corresponding with many others on social media outlets, putting the lie to any claim that she was out of reach or busy?

GENTLE READER: It is true that a friend responds to an urgent message quickly. But friends may have different definitions of what is urgent.

Also, we don't know what else is in your friend's in-box. Not being privy to that correspondence, Miss Manners cannot dictate which message has precedence. She can only hope that your friend sorts her correspondence intelligently and compassionately, taking note of different uses of the word "urgent," from emergencies to mere impatience.

(Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, dearmissmanners@gmail.com; or through postal mail to Miss Manners, Universal Uclick, 1130 Walnut St., Kansas City, MO 64106.)