Couscous,
I managed to swing it one time (and only once) for the spousal unit and myself. Bear in mind that this was on America West, and I was a platinum. Probably one of only three that Am West has.
Anyway, the gate agent hesitated, but went ahead and kicked in the FC when I asked at the gate if there were any FC left. This was mid-day on a Sunday, and the plane was only 1/2 full.
Rare as hens teeth, but it happens.