I get a feeling Delta's doing a lot of overbooking.  I'm at Atlanta airport where around 4 pm, they wanted several volunteers to put off travel to SAN Diego until tomorrow, going via Seattle.  Huge pain in the neck, but they were offering $1,000.  I'm coming back from a trip where I accepted an initial offer of $600 for a less drastic change.  The desk people were desperate for more, and upped the offer to $1,000, including those who'd already signed on.  That's in credits toward Delta fares, good for one year.