Leibowitz, a union lawyer of national stature, was hired to represent the musicians' negotiating committee as well as the Local 2-197, the St. Louis branch of the American Federation of Musicians. In that capacity, he chose not to file a notice—required 30 days in advance of a strike—with the Federal Mediation and Conciliation Service, apparently as part of a strategy to paint the work stoppage as a lockout.

Because of the failure to file notice, the National Labor Relations Board ruled that the strike was illegal, a decision that forced musicians back to the negotiating table. Local 2-197 officials, in their complaint to the New York Bar, say that Leibowitz's failure to file the form constitutes a violation of the Bar's Canon of Ethics.

Meanwhile, a member of the musicians' negotiating committee issued a report critical of the role of the union officials in the strike. "This was probably the most demoralizing settlement in the history of the St. Louis Symphony Orchestra," wrote violist Christian Woehr. "Relations with Local 2-197 are...at an all-time low and many orchestra members view the St. Louis Labor Council as an enemy."