Well, there's a chance that people had used drugs or smoked before, and the smell might still be present. The article acknowledges this, so it's not entirely a myth. While dogs can make mistakes, it's not definitively incorrect.
That's not how the dogs are used. They are told to signal, it's not a mistake. It's a tool of intimidation and a performative gesture towards probable cause. Officers without dogs will just claim "smells like weed" or "your eyes are bloodshot" or a million other things.
When actually searching for drugs, they prefer to destroy the vehicle outright, kick in any box speakers, tear off door panels and fabric, cut open seats, pull out spare tires, etc. They never ever use a dog to find the location of drugs in the car, only for the excuse that drugs might be in the car.
Of course I've never done a search, I'm not a cop... I've been searched many times though, and what I described, I've seen and experienced. Maybe you've done too many trainings and don't know what happens in real life?
