A court decision that could have big implications for how unionized businesses and their workers resolve legal disputes is likely going to come down to competing definitions of the word “may.”

Lawyers for home health aide Tatyana Abdullayeva told a federal appeals court in Manhattan Feb. 19 that she’s not required to arbitrate wage and hour claims against Attending Homecare Services LLC. A collective bargaining agreement between Abdullayeva’s union and the company says workers “may” take their cases to arbitration in the event the union chooses not to file a grievance, Burkett Mclnturff told the U.S. Court of Appeals for the Second Circuit.

“Arbitration is not mandatory,” he said. “It’s clearly permissible.”

A ruling for Abdullayeva could impose some new limits on arbitration agreements, after the U.S. Supreme Court last year generally gave businesses the green light to require workers to sign the pacts as a condition of employment. Forced arbitration—in which privately appointed lawyers, instead of judges, hear legal disputes—have been blamed for allowing public figures accused of sexual harassment to remain on the job without public scrutiny. They’ve also been used to stop workers from bringing class action lawsuits to defend their rights in the workplace.

Judge John Walker appeared to find some merit in McInturff’s argument. He noted that courts have said they’ll enforce arbitration requirements in union contracts only where the language is “clear and unmistakable.”

But judges Debra Ann Livingston and Katherine Polk Faila focused on a different section of the agreement that may shed some light on what “may” means. They pointed to a provision stating that all claims” under specific laws listed in the contract and brought by “a union or employee asserting wage and hour violations shall be subject exclusively to the grievance and arbitration procedures described below.”

“Why does it list all of these laws that are subject to the agreement with no mention of litigation?” Polk Faila asked McInturff.

Competing Cases.

Attending Homecare lawyer Daniel Gomez-Sanchez focused much of his time before the panel on a 2009 U.S. Supreme Court decision in which the high court said a union contract required an office security guard in Manhattan to take his age discrimination claims against her employer to an arbitrator.

He said the court made clear in that decision that agreements that list the types of claims required to be arbitrated are sufficiently “clear and unmistakable.”

Gomez-Sanchez also told the court that the term “may” elsewhere in the agreement doesn’t give workers the right to go to court. “They could choose not to arbitrate, but they couldn’t choose to go to court,” he said.

McInturff countered by turning to a 2016 decision in which the Second Circuit said a collective bargaining agreement didn’t require a porter for a New York property management company to arbitrate race and national original bias claims against his employer. He said the court in that case explained that an arbitration requirement is “clear and unmistakable” only if it “can’t be susceptible to any other reading.”

Abdullayeva in this case was like someone thinking about going into a “haunted house” with a sign that says “all visitors must exit here,” according to McInturff. She has to play by the rules only if she chooses to arbitrate. “She still has the right to decide not to go in,” he said.

—With contributions from Robert Iafolla.