Interestingly, the interviewer specifically asked if I had been to Mexico. I had taken a cruise to Cozumel, but had not listed that on my application...I don't think that's why he was asking because I don't think anyone scanned the passport in Cozumel. In any case, I told him about that.

I didn't leave anything else off, but I did go to a new country (UK) after applying and before approval. The interviewer read the list I had submitted, and asked if there were any countries I needed to add. I told him about the trip, and everything was fine. I have no idea if he was comparing my list with a "missing countries" list.