go back and read Carl's posts. He spoke to the training a couple times and why your situation just isn't reasonable. Basically put, a dog is trained to respond in a particular manner. You may not know what the action to indicate an alert but the handler is. There are times the handler is questioned in court and must explain the alert action and where it is applicable in the case at hand.
as well, if the dog repeatedly is used as a front to search cars without results, that dog really does become a liability. If the dog is shown to be unreliable, every conviction that resulted from previous actions using that dog in that manner are not subject to appeal based on the reliability of the dog.
I understand what you are saying. But, we are right back to relying on one man's word (trainer). Also how would a defendant (if not o.j. with the dreamteam) ever get enough evidence to discredit the officer and the dog. Do you think it reasonable to assume the o.p. will be able to get records where the searches where fruitless where most likely no records exist? Does the average person have those resources? Also, reasonably what percent of times do you think the dogs reliability would be questioned. One in a thousand? One in ten thousand? Even one in a hundred (which is very liberal) leaves a lot of room for people to fall through the cracks. I bet 95 % or better of drug cases end in a plea, of the remaining % realistically how many are going to file a motion to suppress based on an unreliable dog. It may happen sometimes but I feel my view is more realistic and much more common.