My personal opinion is that no "probable cause" tests should be applied to the Fifth Fourth (oops) Amendment, articulable or not unless some hard evidence has been obtained by normal investigative work beforehand.
We are at the point where the "articulable" has been transferred to the behavior of an animal, rather than direct human observation. And this does not even touch upon the problem with the relativistic term "probable."
Just like the relativistic term "reasonable."
I don't have a solution to the drug so-called "problem," except to suggest that we ought to stop the unwinnable war against "some drugs" and let Darwin do the prosecution and punishment.
However, back on topic, having bred, raised, and trained many pups and dogs (I had my own kennel registry with the AKC), some to field readiness, some to only the "green broke" level, I can say with some authority that dogs can be very aware of subtle cues even though the handler is unconscious of those cues.
What's interesting about this is that we credit dogs with the intelligence to react to conscious cues (such as reacting to the smell of pot --or, for that matter, firearms and explosive residues) --yet don't credit them with the intelligence to react to more subtle cues from the handlers which can result in false positives.
I know some of us can get very defensive about the adequacy of rigorous training, yet, knowing dogs as well as other animals, I also know that it is certainly possible for them to "train themselves" to react to unconscious as well as just "very subtle" cues. And this goes way beyond just the sound of opening a can of dog food.
Indeed, the high level of "trainability" of any given dog allows for this actual possibility.
I therefore cannot bring myself to accept the idea that "probable cause" generated by a dog sniffing around a car or a baggage-handling facility at an airport should be acceptable enough evidence to trigger a violation of our constitutional protections.
(The very notion of a dog being "commissioned" as a police officer offends me.)
Let the police obtain hard evidence --not merely "articulable suspicion" of a possible violation --before our constitutional rights are violated.
Especially where the "articulation" involves barking and scratching up someone's car door.
There. I said it and I ain't takin' it back.
Terry, 230RN
Edited for minor corrections.