Significant note: this appears to be a customs screening, not immigration screening. Which makes perfect sense since it's extremely hard for customs agents to

Significant note: this appears to be a customs screening, not immigration screening. Which makes perfect sense since it's extremely hard for customs agents to actually catch smugglers. (Compared to immigration screening which is largely based on hard criteria which human agents evaluate with much less leeway.) The bigger question is whether it's effective - but anything is likely to be more effective than customs agents selecting people to search based on gut feeling.