The only time I've done SDC on an international itinerary is on the way home on the last leg (e.g. shorter connection time in ATL). I went to the check-in counters just after customs & immigration and I asked to be put on the earlier ATL-SEA flight. I was confirmed in "G" class (used a PMU) and the agent put me straight into "F" class on the earlier flight to SEA. Made the flight no problem and got home 3 hours earlier. I don't know if my first class seat assignment, my DM status or it was just my lucky day played into this. The agent who worked with me gave me no hassle and asked no questions.

-RM