You really don't have any way of knowing that Alaska did not charge the passenger for the second seat.

I am glad that Alaska was aware of the situation with the seats and made sure that there was enough room for the passengers that did have reservations on that flight. I know it must have been disappointing to be so close to making it on from standby, but I think it is far better for those in the cabin when adequate room is given.

I've been squished in 1/2 of a seat (and I am not small either) when another passenger could not fit in her seat. I would rather have taken the next flight...........