My guess is that the Ace Ticket sales reps on the phone get a commission, and that Ace Ticket purposely doesn't include the seat numbers online so that you have an incentive to wait until they're open and call the sales rep on the phone.
What is 'Collective Bargaining'. Collective bargaining is the process of negotiating the terms of employment between an employer and a group of workers.
The union may negotiate with a single employer (who is typically representing a company's shareholders) or may negotiate with a group of businesses, depending on the country, to reach an industry wide agreement. A collective agreement functions as a labour contract between an employer and one or more unions.