Being an Asian naturalized citizen, I've noticed this trend:
With a backpack and a roll-aboard, and speak English fluently, I rarely get harassed by customs. They only ask why I'm there and expect me to say 'visit parents'. Did you bring back any food? What kind of food? Ok have a nice day.
The Asian version of Ma and Pa Kettle, with 2 huge suitcases or cardboard boxes per person, plus 2 carry-on bags - now they always get sent for secondary screening post-customs. Maybe they failed to answer questions correctly.
Back when I traveled with my parents, no matter how we adhere to rules and answer correctly, albeit with accented English, it seems if you have too much luggage and aren't fluent, you get secondary bag searched!