WHITE HOUSE etiquette has always been considerably more lax in practice than in theory. For instance, it is an inviolable rule that no guest may leave a White House function before the president has withdrawn. But do you suppose this has ever applied to a cantankerous Supreme Court justice who is beginning to doze off after a badly digested dinner but has just observed a merry president - not the President who appointed him, either - bouncing out onto the dance floor?

Nevertheless, the current administration has set a new standard in entertaining by allowing the Executive Mansion to be used as a setting for receptions by certain groups that pay for a privilege at so much a head. New social rules shall have to be developed to fit these occasions.

Miss Manners does not mean to suggest that a president who won four years of White House residency, fair and square, does not have the right to invite there whomever he wishes, at so much a head.It was our British cousins who set this fashion, not only opening their stately homes, but figuring the worth of, say, tea with a duchess as against biscuits with a countess.

All that Miss Manners wishes is a certain standard of fairness to the consumer. It is one thing to exact precise behavior from guests in the home of their president, and quite another to rent the place out and then turn stuffy about it.

The White House has not been indiscriminate about what groups could use the premises. The Society of American Florists and Ornamental Horticulturists, the American Film Institute, and the United Service Organization are among those that have been allowed to hold at the White House receptions for which they would otherwise have to have rented a hotel ballroom. The USO was said to have paid between $12 and $15 a head for food and service bills, but it can be done for $5 a head, a form of entertainment universally known as Wine and Cheese. The White House social secretary has specified that the package always includes a welcome from either the president or the first lady.

You will notice that this is quite a bargain in the way of convention-time fun. But it would be quite spoiled if the people who participated felt that they were constrained from enjoying themselves as they might in a hotel facility and must observe the protocol expected of non-paying guests.

White House guests are expected to arrive begore the appointed time, wait in long receiving lines to be greeted by their hosts, be extremely careful about engaging the president or his wife in prolonged or controversial discussion and, as has been noted, allow their hosts the unique privilege of being able to go to bed before the guests go home (that alone being nearly worth the price of national compaigning).

A paying guest should, however, be allowed to come and go as he wishes, and should treat with the same respect and courtesy he would any other innkeeper. Now well-bred person would ever be rude to a hotel manager, whatever the provocation, but he would certainly feel free to mention politely any deficiencies in the establishment.

If this is understood, the new form of entertainment should go smoothly. Particulary if the White House takes the trouble to install sufficient bathroom for this clientele, who shouldnot be expected to have to run down all those steps and into the China Room.

Miss Manners Responds

Q: I received a reminder card for a dinner to which I never received an invitation. There is not even a telephone numbed on the card I can call to find out who these people are. I have the feeling that this is a clever maneuver to make me feel obliged to go to a party given by people I don't know and don't wish to know. Do I need to inform them that I'm not coming?

A: Send them a reminder card to remind them of this fact.

Q: At a sit-down dinner, which way does one pass the food, to the right or the left?

Q: Food platters should travel left to right, as most people are right-handed and can serve themselves more easily with the right hand reaching over to the left side. If the majority at the table are left-handed, the food should travel from right to left. However, guests have no responsiblity for such decisions, as they will encounter a platter already marching along as whoever launched it has seen fit. If you try to reverse whatever pattern is under-way, you will end up with the most dreadful traffic jam, to say nothing of gravy all over your lap.

Q: What do you think of ruffled shirts in bright colors for men's evening dress?

A: That is the sort thing of which Miss Manners tries very hard not to think at al.