This pisses me off! The dog is always right - err no, they’re not, however well trained they might be. Anything with a brain can behave unpredictably. Furthermore, degrees of sensitivity are never taken into account with animal “detectors” nor are potential situations where cross contamination can occur (i.e. was the person sitting next to you carrying? Did your carry-on or hold luggage get squashed/rubbed against other luggage that might be tainted?).