You need to calculate the base rate. If only 0.1% of cars are drug mules, then that statistical test might decrease the number of false positives by 10x to 1%.

You need to calculate the base rate. If only 0.1% of cars are drug mules, then that statistical test might decrease the number of false positives by 10x to 1%. But it still means you will search 99 innocent people's cars to catch a single drug mule. Which is well below probable cause, and probably a net harm to society. If they could predict which cars were drug mules with 30% accuracy that would be acceptable I think.