Blue Man Vegas, LLC (BMV) (defendant) produced Blue Man Group in Las Vegas. A seven-department stage crew assisted the Blue Men and musicians. The musical instrument technician (MIT) department differed from other crew departments because its members had specialized skills and cue tracks and interacted primarily only with musicians. “Swing” workers covered absent crew members as needed except MITs. For five years, the Luxor employed all crew except MITs. MITs reported to BMV’s production manager and signed in separately. BMV paid MITs salaries, whereas the Luxor paid crew hourly. The Luxor had a union collective-bargaining agreement covering only Luxor-employed crew members, not MITs. When BMV moved to the Venetian, BMV employed the entire stage crew directly. MITs continued reporting to BMV’s production manager, but other crew reported to department heads under a supervisor. BMV continued paying existing MITs salaries but paid new MITs hired at the Venetian and other crew members hourly. When the union petitioned for a representation election covering all crew members except MITs, BMV argued it should include them. The National Labor Relations Board found the differences between MITs and other crew members significant and ordered a representation election excluding MITs from the unit. After the union won the election, the board’s regional director complained that BMV refused to negotiate with the union. BMV countered that excluding the MITs made the bargaining unit inappropriate. The board ruled for the union, and BMV appealed.