Years ago, at KIDL,during breaks I would stand on the balcony of the International Arrival building and watch experts with customs screen incoming passengers.
It did not take long to realize they were watching the passenger as they felt around in their baggage. If the passenger showed no outward telltale signs,, thirty seconds and they were cleared. They had body cavity searchs way back then, by doctors and nurses.
They did the odds, 99.9 per cent of the people were of no interest, hassling them was stupid. It was the tiny minority they were very adept at spotting. They were professionals at spotting the bad guys.
The morons of TSA are washouts from the plumbers union.