Networks try to make amends for the cacophony of their Saturday morning kiddie schedules with occasional high-quality weekday afternoon specials for children. Why it is assumed children will not sit still for sanity and decency on Saturday morning remains a mystery. Apparently such things are inefficient at moving Honey Buns and Sugar Smacks.

It is hard to be anything but extravagantly grateful, however, for programs like the "Special Treat" whipped up by NBC today, a one-hour drama with music called "The Tap Dance Kid," at 4 on Channel 4. This program, written and directed by Barra Grant (daughter of Bess Myerson) is warm, funny, touching, upstanding and humane. Adults should be so lucky as to have such programs produced for them.

In Barra Grant's film, from a book by Louise Fitzhugh, 3-year-old Willie Sheridan is frustrated in his quest to be a tap dancer entraordinaire by his father, who thinks tap-dancing contures outmoded racial stereotypes of shuffling blacks and keen on upward monility wants Willie to set his sights on amore lucrative career. But Willie's sister Emma, a practicing attorney [WORD ILLEGIBLE] though only 12 comes to his defense.

Emma is a founder of the Local Children's Rights Crusade, and her credo is, "The Constitution does not limit happiness to grown-ups." The film sanctions disobedience of one's parents in those cases where they are clearly in the wrong. This may sound moderately radical in theory, but Emma can hardly be argued with when she tells her father, "You don't break promises to children; it's the worst crime in the world."

The networks and local TV stations ought to remember that one themselves.

As young Willie, James Pelham couldn't be better, and when he tap dances, in a derby and bow tie, he lights up everything in the world. But Danielle Spencer, as Emma, is an even more formidable young performer. Each week her off-the-wall, pungent deadpan proves the only interesting thing about ABC's sit-com, "What's Happening," and she is her inimitable inscrutable self in "Kid" as well.

Also seen very briefly are Claudia McNeil as a nightclub singer named Mabel who has found the peace that comes from "loving what you do," and, as an aspiring hoofer, 9-year-old Gene Williams Jr., of Columbia, Md.

Considering that much of what's on television reflects little thought and care, it may seem a paradox that a low-budget daytime program like this "Special Treat" can be so good. The reason is probably that the networks look upon them chiefly as goodwill builders, not profit-makers, and so do not hover over every little detail of production. Hooray for the television that is safe from network executives, and for "The Tap Dance Kid" in particular. It is a wonderful show.