Does not sound like the same screening in the US. No way would the lighters in the tray be allowed on a US flight.
It sounds like airports in other countries are not screening as tightly for US bound flights as airports in the US.
I fly a lot for business and I see people getting caught with lighters and such all the time. In fact the last airport checkpoint I went through had a row if confiscated lighters sitting on top of the x-ray machine.

The upside is you can go out of the terminal where smoking is allowed and just pick up a free lighter that a departing passenger tossed. Leave one going in and get one coming out.