Old topic I know.... new experience. Booked SMF-CUN a couple months back. E- sold out several weeks ago. Logged on today (flight in a few days), about 4 dozen E+ seats still available, and several of them were no longer blue, but instead white. Immediately changed my seats to these new spots with no charge. Only 6 out of 20 F sold, with nobody on the FC upgrade list. It's been $700+ to upgrade ever since I booked, so I'll be interested to see what it'll be at the airport.