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.
Integrative bargaining is important because it usually produces more satisfactory outcomes for the parties involved than does positional bargaining. Positional bargaining is based on fixed, opposing viewpoints (positions) and tends to result in compromise or no agreement at all.