Through no fault of their own, more families seem to be staying together these days.

College students have less money with which to practice the traditional summer pastime of hanging around away from home, doing nothing. People on their first jobs have less with which to establish sovereign (no regular laundry days) domiciles. For such reasons, not to mention those of affection, great hulks of children who might otherwise have vacated the premises so fast that the wind would have knocked their parents over are staying in, or returning to, their original homes.

Actually, why isn't affection being mentioned?

Why doesn't the grown-up child say, "This is the happiest place I know," rather than "I'm broke," when explaining his presence? Didn't anyone ever teach him manners? No wonder he's broke.

But even if manners have always prevailed in the household, certain adjustments are required when the little ones become bigger than the big ones. Miss Manners is far from suggesting that etiquette is based on deference to power, although it does make some logical sense and is not unknown in the branch of the field called diplomacy. Socially, however, chivalry introduced the quixotic concept of the strong yielding to the weak.

Now we have something of a mixture of the two. In family terms, that means that children yield to their parents because the parents are financially and otherwise stronger than they, until they are able to yield to the parents because the parents are more fragile than they. Both are called "respect."

We are talking here about deference of manner. Any child with spunk will long since have learned how to toddle respectfully around parental authority.

But as the nature of the authority changes, so do the daily rules of etiquette to be practiced by both parent and child. The parent has much the harder task, in that he or she must scrupulously maintain the fiction that the child is now a responsible human being. (This is easiest done when he and she go off together and shut the door to laugh or despair about the ridiculousness of this premise.)

The child's job is to trade one sort of accountability for another. In return for freedom from being continually brought up, he must portray himself convincingly as one who has been properly brought up.

The polite and independent person always wishes to do his share. Miss Manners is not prepared to make general rules about financial contributions by grown-up children (except to say that the proper term is "contributing" or "helping out," not paying rent), but contributions of work to the upkeep of the household are obligatory. Anybody who expects to be waited on should also expect to be scolded.

Mutual respect is to be shown in use of common items, such as cars or television sets--adult children are expected to take into consideration the preferences of those with whom they live.

Information about general plans ("I'll be quite late tonight--don't expect me for breakfast") should be volunteered, so that rigorous questioning becomes unjustified. And of course, all guests are cleared in advance with other members of the household.

The object, in sum, is to show that the child in need of guidance has been replaced--by someone his parents no longer recognize.Q.I have recently purchased a straw hat, and am curious as to its proper use.I feel it could be worn to a picnic. However, I wonder if it is suitable to wear to museums, shops, classes, receptions, church or ceremonies.

May it be worn inside and outside, day and night? Does the angle at which it is worn convey any message? Does the color of its band reveal inner thoughts? I am indeed anxious to learn the subtleties of this charming modern oddity.A.Do not, repeat, not, wear your hat to bed at night. That conveys the wrong message, and makes you feel as if you had slept sitting up in a train. Goodness, gracious. The queries a respectable etiquette lady is expected to deal with these days--speaking of modern oddities.

Miss Manners refuses to be amused by the concept of the hat. Individual hats may be, and sometimes should be, amusing (but not, as gentlemen have for centuries persisted in thinking, hilarious), but the idea of the hat is basic to the civilized life. Look how things have gone without it these last few decades.

A hat is not just suitable for wearing in museums, shops, receptions, church and to ceremonies (take it off in class, you clown), but essential. It is worn during the daytime, indoors and out, but not in one's own house. When you have mastered this, come back and Miss Manners will reveal to you the subtleties and inner meanings. You are not ready for them yet.Q.My son is on two basketball teams, one at his elementary school, the other at the YMCA. Invariably, there is some father attending the game who yells out instructions and very rude comments to all the players, coaches and referees.This type of person disrupts the game, embarrasses the children and, by his actions, shows poor sportsmanship. Please tell us quiet parents how to deal with this loudmouthed fool without being rude ourselves..One person's loudmouthed fool is another person's sports enthusiast. The etiquette of sports audiences is somewhat different from that of concertgoers (although not too far from that of die-hard opera lovers). Miss Manners is not saying that there are no rules, nor that this gentleman has not violated some, but let us sort them out first.

"Git 'em," addressed to a player, is an instruction, for example, and "Kill the umpire" is certainly a rude comment. But both are within the etiquette of the situation.

Where children are involved, you may, and should, set higher standards than are normally practiced. Children should not have to listen to obscenities, embarrassing criticisms, confusing instructions or recommendations of poor sportsmanship while enjoying a bit of healthy recreation.

If there is one person to whom a loudmouthed sports fool (oh, dear, there goes Miss Manners' pretense to neutrality) will listen, it is the coach. You parents should pass on your complaints to him. If he steps menacingly in front of the offender and says, "I'm in charge here, and I won't have you throwing my players off their game" (or whatever it is they say--Miss Manners has difficulty sounding like a menacing coach), your problem will be solved.Q.I have always been taught never to turn around in a church to watch the bride walk down the aisle. I have always thought that the polite response was to turn somewhat sideways at most, to see her as she passed.I have been to several informal weddings recently, where the entire congregation about-faced to watch the procession. Incidentally, several of them took flash pictures of the entire ceremony.How would you like to spend months investing your emotional and financial resources in one great splendid moment of glory, and have all your friends and relations pretend that they don't notice that you look any different from usual?Of course, there is supposed to be a stir in the congregation when the bride enters. How much of a stir is the only question.

Often, it is the custom for the congregation to rise at the beginning of the processional music, and actually face the rear of the church to watch the procession. If not, then they may certainly turn their heads to look. Turning the entire body or standing on pews to get a good view is not permitted.

As for taking pictures--Miss Manners always feels like such a wet blanket, reminding people that a wedding is a solemn ceremony, and a church wedding a religious occasion, as well. But the fact is that, contrary to popular practice, the wedding is held to get people married in the eyes of God, not in the lens of the photographer. Q.Is there anything wrong with leaving a hairbrush face up on a table, even if the table isn't going to be eaten on for three more hours?A.Eeew, disgusting. Get that thing off of there.

Copyright (c) 1983, United Feature Syndicate, Inc.