It's not unusual for someone to have millions in accrued frequent flyer miles, worth tens of thousands of dollars in services and products. Miles are earned for lots of activities besides flying: hotel stays, car rentals, credit card purchases, mortgage closings, etc. The airlines have let people transfer miles in their estates forever. It may be Delta's right to make this change to their program, but it is a big change in policy nonetheless. It's just more proof that the airline industry has become one of the scummiest groups of companies in existence.