This promo won't affect DL's liabilities or revenue by any meaningful measure.
Although many mileage earners generally assign a value ranging from one cent to two cents to each mile earned, which approximates the revenue received by the airlines when they sell miles to partners, the airlines generally record much smaller liabilities for outstanding miles held by frequent flyer program participants.
For example, Delta records a liability of $22.02 per 25k standard award ticket that it expects will be redeemed. This amount represents DL's marginal costs in providing the average round trip award seat. More fully discussed in:
http://investor.delta.com/EdgarDetai...2423&SID=04-00 (pp 12-13).
So even if every participant in this promo will eventually redeem their 10k "prize" toward a standard award (history says they won't), the liability to DL is just $8.81 per 10k prize.
The numbers involved in this promo are insignificant. There's no potential revenue or liability manipulation. When DL sells miles to partners (Amex, hotels, car rental companies, etc), most of the revenue is deferred and recognized over 30 months:
We sell mileage credits in the SkyMiles® frequent flyer program to participating partners such as credit card companies, hotels and car rental agencies. A portion of the revenue from the sale of mileage credits is deferred until the credits are redeemed for travel. We amortize the deferred revenue on a straight-line basis over a 30-month period. The majority of the revenue from the sale of mileage credits, including the amortization of deferred revenue, is recorded in passenger revenue on our Consolidated Statements of Operations; the remaining portion is recorded as an offset to other selling expenses.
http://investor.delta.com/EdgarDetai...2423&SID=04-00 (p F-15)
Although airlines and credit card partners don't often let on how much is paid for miles, the recent two year Amex prepayment deal reveals that Amex mileage purchases are perhaps about $250 million per year. At two cents per mile (I suspect that Amex pays less), that's 12.5 billion miles annually.
http://news.delta.com/article_displa...rticle_id=9520
At 12/31/03, total outstanding unredeemed SkyMiles exceeded 357 billion, and based on historical trends, it is likely to be in excess of 372 billion as of 12/31/04. Giving away 10k miles in this promo over a very short time frame to a relatively small number of people won't affect these numbers in any meaningful way.