DEAR MISS MANNERS: I am planning a celebration of my late husband’s life, and being good to myself by having it catered. Nothing fancy, but I am worrying about how much food and drink to order.

In light of the current habit of disregarding a request for a response, could I include on the invitation something like, “If you attend without an RSVP, kindly do not eat or drink anything”? I am sorely tempted.

GENTLE READER: People are sorely tempted to do many things, but civilization is hinged on thwarting those baser desires.

Meanwhile, Miss Manners is left wondering how you would even go about policing those guests who show up unannounced. A rap on the hand as they reach for a shrimp? An elaborate pantomime of handing them a pretend glass and not filling it?

Unfortunately, the only proper thing to do with these brazen guests is to express surprise at their appearance. Courting insult in the form of threats is a rude and fruitless activity.

However, if you find yourself running low on refreshments and those same guests have the gall to complain, you may say, “Oh dear, I’m afraid that I only planned for those who told me they were attending.” And plan not to invite them next time.

DEAR MISS MANNERS: When is it necessary to give a card, and to wrap a gift?

For the former, I’ve always felt that it’s appropriate when sending greetings through the mail, but not face-to-face. I’ve consistently told family to please not give me cards in person, yet they continue to do so anyway.

I find them a waste of paper (and money, as some of the fancy ones are very expensive) when you’re just going to say “Happy birthday” or “Merry Christmas” directly to them anyway on the day in question. The sole exception is when they are being used as a gift wrapper themselves, such as with cash or a gift certificate.

As for the latter, I consider it suitable when the element of surprise and anticipation is important -- such as during a party, at a shower or opening Christmas presents -- but again, I think it wasteful to wrap gifts when shipping them to the receiver’s address or when the gift is spontaneous.

Lastly, on the issue of gift-wrapping, does an authority on etiquette have an opinion on gift bags vs. boxed and wrapped gifts? It had never occurred to me until people started bragging about how easy it was to “shove it in a bag” instead of wrapping it.

GENTLE READER: The purpose of a present is, Miss Manners wishes to remind you, to show gratitude or appreciation. Efforts to make the act of giving as efficient -- in other words, effortless -- as possible therefore invalidate the reason for giving the present in the first place.

By contrast, wrapping and accompanying notes emphasize those reasons. Were efficiency the only standard, one could merely slow down the car and toss the present onto the porch.

(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, Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO 64106.)

DEAR MISS MANNERS: How long do you stay at an office party at your boss’s house when you really just want to “make an appearance”?

I’m just not sure if there is a protocol as to how long “an appearance” is.

GENTLE READER: The minimum length of a decent appearance must pass the highly subjective test of not leaving the hosts feeling that the two necessary exchanges -- the hosts’ greeting at the door, and the guests’ seeking them out to thank them -- have merged.

It is unfortunately difficult to reduce this to a fixed number of minutes, although it is presumably shorter at a large party. This often means that staying longer than you feel is absolutely necessary is the only guide. Miss Manners prohibits cheating -- such as taking leave of the husband, knowing that it was the wife who welcomed you.

DEAR MISS MANNERS: My son happens to have special needs. I am a single parent, and I try to expose him to as much in life as possible, as I think it will help in his development (he is now 17 years old).

I’m still hurting over something that happened two years ago. My nephew -- my son’s first cousin -- was getting married. While all the other cousins of all ages, including toddlers, were invited to the wedding, my son was not.

Further, my sister-in-law, my nephew’s mother, invited me to an all-family gathering the day after the wedding, but said, “I don’t know what you will do with ____ (my son).”

I know a lot of time has passed, and there have been other reasons for my brother and me to have issues. But I am having a real problem letting this go “for the sake of the family,” especially now that our mother and father have passed and we are all we have for each other.

Am I wrong in being hurt? How can I let this go, or should I even let this go? I have tried to talk to my brother about this, but he will not have a conversation.

GENTLE READER: Families have been torn apart by actions far less egregious than refusing to treat someone as a family member because he has special needs. It is no surprise that their actions still rankle, particularly if you did not take exception to them at the time.

But for the same reason, your brother and his family do not understand how reprehensible their actions were. Miss Manners does not see a need for conversation with your brother so much as clarification, which is more easily delivered in written form. There is little to be done about the wedding at this date, but it is worth saying to your brother that if his family cannot treat your son as an equal member going forward, they cannot reasonably expect to have any relationship with his mother.

(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, Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO 64106.)

DEAR MISS MANNERS: Several years ago, our guests stopped sending us thank-you notes. They stay at our weekend house for days on end, being wined, dined and pampered, and then we receive an email: ”It was so lovely. Thanks.” Now it appears they no longer call or send birthday cards. On my birthday, I receive “e-cards” and am told where to go on the net to see them. Should I feel content with this? At least they remembered my birthday (although doubtless because a programmed reminder popped up on their e-calendars).

GENTLE READER: Your guests would likely protest that they did not stop sending thank-you notes and birthday cards. They merely reduced the amount of effort required on their part. If they were feeling defensive, they might even assert a moral improvement in their approach -- the virtue of responding more quickly or saving a piece of paper. None of this would convince Miss Manners, who, like yourself, cannot help thinking that the reduction in effort reflects a commensurate reduction in the sentiment.

DEAR MISS MANNERS: My parents, who own a large empty nest, offered to provide free room and board to a cousin while he was a student. After a couple of years, my mother was tired of having the cousin living with them, although my father rather enjoyed his company.

Eventually, my mother had harsh words for the cousin, who abruptly moved out, with angry feelings on both sides. Now my mother is angry that after cooking for the cousin and making him part of their lives, she not only has not pleased his family, but they openly dislike her.

The cousin’s family told me that my parents expected him to help maintain the large empty nest; their version is that my parents exploited him by expecting him to do chores. (When my siblings and I lived at home, we did a lot of chores, and I’m sure my parents thought the cousin would do the same when living there.) I don’t know who is right or who is wrong, but I do know everyone is mad.

GENTLE READER: Instead of harsh words at the conclusion of this arrangement, your parents should have issued some cautionary words at the beginning.

Seasoned guests may not need to be told that a long-term visitor is more like a member of the family than a guest (and in this case, he actually is a member of the family). But a youth who is asked to help could have it explained to him that while members of the household have privileges -- they usually arrange their schedules for their own convenience, and come and go freely without consulting the hosts -- they also assume responsibilities.

That the cousin’s parents don’t understand that, either, is discouraging, although not surprising. Miss Manners is guessing that the most that can be done to resume friendly relations is for you to point out that your parents treated the cousin as one of their own.

(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, Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO 64106.)