David A. Karcher, executive director of the American Society of Cataract and Refractive Surgery, could see the costs mounting as workers set up his group's convention at the Pennsylvania Convention Center in 2002.

"I watched two guys take three hours to put a tablecloth on a six-foot table," Karcher said Friday, describing the hassles and ballooning costs he experienced. "When I went over to question them, they told me to mind my own business."

Karcher was furious and didn't keep it a secret. "I have never been confronted with such a negative labor situation as was experienced in your city," he said in an interview at the time. He canceled his group's 2008 and 2012 conventions in Philadelphia, vowing never to return.

Except now he is, having just signed a deal to bring 13,000 eye professionals to the city in 2022 for a convention expected to fill 37,359 hotel rooms and generate $40 million in economic impact.

It's that kind of business that is at stake Monday, when the Convention Center Authority's lawyers face attorneys representing the carpenters' union that lost its right to work at the center nearly three years ago.

Publicly, the city's tourism officials won't say much, in light of the litigation. But privately, they are worried about what might happen after Pennsylvania Labor Relations Board hearing examiner Jack E. Marino hears testimony and arguments to decide whether the Convention Center committed an unfair practice against the union.

In May 2014, the center and its new private-management company, SMG in West Conshohocken, pushed the carpenters — and five other unions at the center — to sign a new customer-service agreement under a quick deadline, even as some of the unions were involved in collective bargaining over wages and benefits.

Four of the six signed immediately. The carpenters and Teamsters did not, but signed a few days later. By that time, though, their work had been distributed among the four other unions.

Protests, picketing, and litigation ensued and, famously in Philadelphia labor history, officials from the other unions, including John Dougherty, head of IBEW Local 98, led their members across the carpenters' picket line.

What also ensued was an intense marketing drive by the city's tourism industry, promoting a changed Convention Center.

Gone, they said, would be the kind of jurisdictional disputes that so plagued Karcher's group. Costs would come down because the unions that replaced the carpenters' work earned less and had fewer nonworking union supervisors. They would be more friendly, willing to let exhibitors save money by doing more of their own work.

Meanwhile, the tourism marketers said, management had also reformed, bringing in a new board chairman, lawyer Gregory Fox, who pushed the authority to privatize the center's management, putting it under the control of SMG, which manages convention centers nationwide. Fox was recently reelected as chairman.

"We've been able to rebook a lot of shows," vice chairwoman Heather Steinmiller said at Friday's meeting of the Convention Center Authority board. Some, she said, had told Philadelphia's convention sales force, "don't call, don't come talk to us, don't write, don't send flowers. The rebooking is the real proof that things have changed."

The sales pitch worked, wooing and winning association leaders such as Karcher. "I'm looking forward to coming back," he said Friday, citing new hotel construction, the city's walkability, and an improved labor situation with fewer unions.

Soon after the carpenters and Teamsters lost work at the center in May 2014, they filed charges of unfair labor practice with the National Labor Relations Board. The NLRB declined to hear it, saying that the Convention Center was a public entity and that the case should be heard by the Pennsylvania Labor Relations Board. Besides the facts, Marino must also decide whether the PLRB has jurisdiction.

The authority countered by suing the carpenters in federal court on racketeering charges, accusing them of disrupting the 2015 Philadelphia Auto Show as part of a pattern to interfere with the center's business. Federal judge Nitza Quiñones Alejandro has yet to rule on the union's motion to dismiss the suit.

Since then, the Teamsters have been allowed back into the building on a limited basis and the then-head of the carpenters union, Edward J. Coryell, was pushed into retirement by his boss in Washington. Philadelphia's carpenters' union locals were taken over by the Northeast Regional Council of Carpenters based in Edison, N.J. Coryell's son, Edward Coryell Jr., was transferred there, away from running the union at the Convention Center.

"We believe our position is strong and that we are on solid legal ground to have our members return to their jobs at the Convention Center. We trust in the process and believe the judge will make the fair and right decision," said John Ballantyne, who leads the carpenters' union from his office in Edison.

But it's far from over. Marino's ruling can be appealed to the entire three-member PLRB board, including Albert Mezzaroba, a politically connected lawyer and former chief executive of the Convention Center.

Meanwhile, Karcher, the executive director of the cataract group, will be watching.

"If the jurisdictions increase," he said, referring to the number of unions, "I think I have the right to cancel the contract."

Is that what he'll do if the carpenters return?

"Yes," he said. "It was just that bad."