DEAR MISS MANNERS: In a restaurant where there is a sign that states "No shirt, no shoes, no service," why are people allowed in to eat wearing sandals or flip-flops? You know, the flip-flops that we used to wear when we went to the swimming pool.

I see people all the time wearing flip-flops in restaurants. I thought the sign meant if you do not have shoes on, you will not get served. But I see now that most restaurants do not have that sign up like they used to.

GENTLE READER: Do you have any idea what it is like to establish any sort of dress code nowadays?

Employers direct their workers to dress professionally, in terms of whatever the particular profession happens to be. Hosts beg their guests to dress up for their important occasions. Schools issue rules banning vulgar and bigoted outfits. Businesses try to establish a tone they expect their customers to follow.

And what does it get them? Code violators who consider themselves to be fighting -- sometimes with lawsuits -- for the noble cause of freedom of expression.

It appears that only clubs with rough bouncers are able to inspire people to dress symbolically for the activity in which they are engaged.

So Miss Manners doesn't wonder that those who write such codes back away from battles over strict enforcement, especially over such hair-splitting questions as what constitutes a shoe. Perhaps if they notice they are losing customers who want a more dignified -- or less smelly -- atmosphere, they will act.

Or they could just hire a toughie to stand at the door, pronouncing people "tacky" and turning them away. Then the lines will form around the block.

DEAR MISS MANNERS: My sister sent me a text saying she needed to know who from my family would be attending her daughter's wedding. It was five weeks from the wedding.

It said she needed to know ASAP, as it was a small wedding, and good friends could not be invited because of family. She didn't see a reservation for my daughter and son-in-law because the block of rooms at the hotel was full. (They have reservations at a nearby hotel.)

I was very hurt, but she claims I withheld information from her and I am too sensitive. Am I wrong to feel as I do?

GENTLE READER: Yes. And it strikes Miss Manners that for someone with tender feelings about herself, you are amazingly insensitive to your sister's needs.

The lady is planning a wedding. She needs to know who is attending. She went so far as to check the hotel reservations searching for an answer about your family.

But although they decided to go, and took care to notify a hotel, they did not have the courtesy to answer the invitation.

At most, you could wish that your sister had confronted the rude guests, rather than going through you, possibly out of delicacy (or possibly because she didn't have their texting address). But your indignation should be directed at your daughter and son-in-law for embarrassing the family.

(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 was taught in grade school by my music teacher that it is disrespectful to clap after the singing of the "The Star-Spangled Banner." I have not clapped after the national anthem in more than 30 years. Is that wrong?

GENTLE READER: You were taught correctly. It is an anthem, sung for the glory of the country, rather than to amuse the listeners or to congratulate oneself on having remembered the words, if not the tune.

However, as in the case of people who wear flag-themed clothing, Miss Manners notes that many have come to believe that ignoring the rules of respect is somehow indicative of patriotism.

DEAR MISS MANNERS: A close friend of about eight years asked me to help her plan her daughter's wedding. I went to many venues and florist appointments with her. I was so excited about this wedding and her sharing the planning with me. I thought I was so special.

As we were driving to lunch the other day, she told me about how she had worked for over seven hours to do the seating chart and how I was going to be so mad at her.

I am acquainted with many of her friends, and we have a couple of mutual friends we both socialize with, all of whom will be at the wedding. She explained that she is so sorry, but she just didn't know what else to do with me, "so I put you at the table with my household staff."

I feel I must have misinterpreted our relationship greatly. I feel at this point if I go, it will not be with a joyful heart but as a duty. I emailed her expressing my apology that we would not be attending (the wedding is still three weeks away).

She left me a message stating that she would never force me to do anything I did not want to do, and how she was hurt and found it disrespectful of me not to call her and talk about it. She said she and her husband worked all night to find another appropriate table for me and my husband.

She also raised her voice in another message and asked what was wrong with me to upset her at this time. Goodness, why would I want to go to a wedding where I do not feel welcome?

GENTLE READER: Indeed -- although wicked Miss Manners might have been tempted to take advantage of the seating to pump the household staff for gossip.

Miss Manners' advice now depends greatly on what reason -- if any -- you gave as to why you would not attend. If you gave none (generally the best option, as it doesn't tangle you up in excuses and half-truths), then keep telling her that you are so sorry, but that you simply cannot attend.

If you told her the truth -- that you felt that you were being treated poorly -- then tell her that you didn't realize that having you there was so important to her and that now you've made other plans (which may actually mean plans to make plans).

In any case, a friend who raises her voice and doesn't mind treating you like an employee -- no matter how important she deems the occasion -- is probably not one that you are sorry to lose.

(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 am a young woman in her early 20s whose friends are being proposed to and becoming engaged. I have noticed that when these young ladies present their happy news in social settings, the other women ask to see the ring. When the ring is obligingly passed around, many women try it on.

I seem to be the only one who doesn't do so. I have always assumed that the engagement ring was something that a woman other than whom it was presented to was not to try on, since it is ostensibly a symbol of the promise between the happy couple to be wed.

My friends say it doesn't matter as long as the lady who owns it has passed it around, since that signals that the other ladies may try it on their hands, but I am not quite so certain. Am I wrong to simply admire the ring in my hand (rested on the palm) rather than on it?

GENTLE READER: Ladies old enough to wed should have emerged from the Show and Tell Years, but apparently many have not. Passing around the engagement ring is only slightly more decorous than passing around the bridegroom.

When it gets to you, Miss Manners encourages you to express admiration, but you are under no obligation to bite it, try it on or ask the price.

DEAR MISS MANNERS: If I attend a cocktail party in a friend's or acquaintance's home, and I know from the past that wine will be served in disposable plastic cups and food will be served with plastic forks on paper plates, is there any chance in the world that I can get away with bringing my own mess kit?

I've done it at street festivals and it's fairly discreet, though it does attract some attention. I carry a small collapsible stainless steel cup wherever I go, and I wonder if it would be acceptable to use at parties.

I can think of several arguments for this practice and several against. I do wonder if I might be at more of an advantage trying this now, rather than five or 10 or 20 years ago; now the trend is to appreciate efforts toward "greening."

GENTLE READER: Much as she loathes eating from soggy plates with fragile forks, and drinking from crackable cups, Miss Manners is even more opposed to criticizing one's host -- even by implication, and even in the name of saving the planet. The clear indication of your mess kit is that visiting that person's home is like camping out.

Besides, there is no chance in the world that producing a collapsible cup at a cocktail party can be done so discreetly as to make it acceptable. The ban does not extend to the street fair, for which there is no host to offend, and at which pitching camp may go unnoticed.

(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.)