Most major airlines have frequent flyer programs that permit passengers to earn free tickets based on the number of reward miles they have flown. A Southwest Airlines annual report contained the following note: Frequent Flyer Awards The Company accrues the estimated incremental cost to provide transportation: for travel awards when earned under its Campany Club frequent flyer program. The phrase incremental cost refers to additional expense associated with an extra passenger taking the flight (e.g., the cost of a soft drink and a snack). Required: 1. What cost measures other than incremental cost could Southwest use? 2. What account should Southwest debit when it accrues this liability?