SOME CHILD CARE experts and physicians are disturbed by the large number of notices, on everything from milk cartons to shopping bags, being used to depict missing children. They fear that children are being bombarded with these ads and may become inordinately fearful of being followed or kidnapped by any adults they do not immediately recognize.

We suspect, however, that this is an overreaction. Between children who are unafraid of strangers, who accept rides from them or open doors to allow them into their homes, and children who are wary when they are approached by adults they do not know, surely the latter are safer.

Long before anyone thought to run a national campaign depicting missing children, there was a belief that children should be taught early whom to trust and whom not to. Trust, obviously, family members and relatives. Trust neighbors who are friends and other adults who are close friends of the family. Trust school crossing guards, teachers, the police on the beat. Teach children to approach people behind the counters or security guards if they get lost in department stores. Get one's neighborhood involved in becoming more of a community, in learning about one another, becoming friends and looking out for each other's children. Anyone else is a stranger with whom a child should be more careful.

Knowing these things would help make a child feel secure by letting him know his neighbors and other adults in his life as friends. If a child looks at the face of a missing child on a carton of milk and asks his mother or father why the face is there, an excellent opportunity opens for a valuable discussion.

Few of the many children listed as missing have actually been kidnapped by strangers. Some have been taken by one parent. Most have run away from home. Some children are sensitive and may be frightened by the notices, but plenty of experts say such fears are rare. The same children may be equally frightened by the television shows they watch.

Unfortunately, there are relatively few communities around the country where there is no reason to be afraid because there are no strangers to speak of. But it is better if children fear strangers than if they trust an unknown person who has not earned their or their parents' trust. If those ads convey that message, that's not a bad idea.