Unfortunately it didn't display that there was only one seat left in this fare class (otherwise I wouldn't have attempted booking 2 tickets), but it looks like their multi-city display is slightly different from the looks of their regular round trip display.
I don't expect them to honor the fare for my friend, but I'd now like to get out of my ticket, which is kind of meaningless since my friend won't be able to afford the more expensive fare.
Going to try to call the San Francisco office when they open and see if the DOT 24 hour rule applies to cancel this. I'm hoping it will, since I booked it on their US website.