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.
Stage 1: Preparing. The basis of collective bargaining is management engaging in dialog with the workers collectively, and as such, the first stage of collective bargaining is organizing a group to represent the workers. If a trade union exists, then such unions usually take up the role of representing the workers.