Experts suspect that the Washington-Baltimore area has become the national hub of the seasonal "Nutcracker" business. Some authorities consider it to be an illegal traffic, since the authentic Lev Ivanov choreography is difficult to detect even in versions advertised as "traditional." And consumer specialists warn that it is hard to determine which are the professional productions, because standard practice allows for the use of student dancers in children's roles.

Teh two area "Nutcrackers" which must be labeled "school" productions are Virginia Ballet's and Dance for Washington's.

The Virginia "Nutcracker" at Woodson High School in Fairfax through tonight is an unabashed student recital. Typical of choreographer Tania Rousseau is the army of pupils that parades across the stage. Mostly they are girls and young women, rightfully proud of standing and moving en pointe. But there are battalions of them. So many that the thread of the story snaps. Without doubt, this production serves the performers' parents to a report card.

Dance of Washington, presenting Karoly Barta's "preparatory workshop" version of "Nutcracker" through tonight, has a plus in Ted Naos' white cutout sets. They do suggest Christmas on the difficult-to-decorate stage of Constitution Hall. The sole professional in the cast is Barta himself, in the dual role of Drosselmeier and Mouse King. He behaves with some dash, but almost everyone else looks automated performing his choreography. Not only are the dances pedantically meticulous, but even the mime is so stylized that there are often no connections between action and response. The children on stage are Dance for Washington students, while most of the difficulties are managed by senior pupils from elsewhere, including the American Ballet Theatre School in New York. For them all, and for the audience, Barta's "Nutcracker" may not convey the joy of dancing, but it certainly is a lesson in discipline.