When I made a reservation to fly SFO-PHL-AMS and return for late October, only the PHL-AMS leg was available for the SWU. I was waitlisted on the other legs.

I checked ITN every few days to see what availability was, and sure enough there were no seats showing in G for the domestic. This morning, when I checked, there were now G seats available on the domestic legs (and they'd changed the PHL-SFO return from a 757 to 767!). I called the international desk and was told that I had been "cleared off the waitlist and was now confirmed in seat 4A for the entire trip".

I don't know if it took a human to do that, or if I was confirmed into Envoy when they (obviously) did a re-allignment of the F class seats.

Lesson? Keep monitoring ITN and it never hurts to call.