Out of a number of times, I only got questioned only once and at LAX. That was my first SIN trip early last year. I had 3 bags (one bought in SIN) and not much in each one. (I was lazy & didn't combine into 1 or 2 bags). They asked me how long in SIN & I said 2 days. Red flag in their eyes. They asked me how I could afford to fly to SIN for a short time. Try cheap ticket & mega miles! Showed them a printout of previous overseas trip. Gave the customs officer an education on airline points, cost per mile, etc. After going through my bags & finding nothing illegal, they let me be on my way. I did tell them I may miss my flight to ONT.

On future trips, when they asked me how long in the country, I will count the time from departure from the US to entrance to the US. I will say I have been gone 5 days although I spent 2 days & a night in SIN. Not being dishonest but a different way of answering their question. On my future trips, I only had one carry on bag. They say, only one bag? I tell them Rick Steves (PBS videos of Europe--they usually recognize him) recommend to travel light. No troubles since.