I don't think the 'unconcious handler cueing' is convincing or rational ... not in this case
I'll give my reasons
It was of no benefit to Mr Grime to lead his dogs into giving false alerts ... their accuracy is what matters to him, Whether they accurately alert, or accurately non-alert is of equal value to any investigation ( the cueing accusation implies that his dogs are only of value when they do alert, and that is simply not the case )
Getting on to specifics though
The first time Eddie, the cadavour dog is introduced to the investigation is when he is brought to the McCann's apartment. Immediately, still at the front door, Mr Grime notes a change in Eddie's demeanor ... he is already in a state of excitement ( with no cue from his handler )
Eddie enters the apartment first ... he is on a free search
He alerts in seperate locations. There can be no question of Mr Grime 'cueing' Eddie at this point because he ( Mr Grime ) had no idea which locations were significant
When Keela, the blood dog is brought in, Mr Grime already knows which locations are significant ( the shelf in the wardrobe and the area behind the sofa ) and he specifically directs Keela to those locations ... cueing ? ... or simply taking the logical and necessary steps to validate the alerts Eddie had already made ?
In any event, Mr Grime pays great attention to the wardrobe where Eddie had already alerted. He directs Keela to it, and has her jump up onto the first shelf ... he even lifts her onto the second shelf
Now that might be interpretated as 'cueing' by some, but here's the thing ... despite all that handler direction, the dog did not alert
When it came to the vehicles, it is quite logical that the McCann's car was the focus of the most thorough investigation ... both dogs had already alerted in the McCann's apartment afterall
Had the dogs alerted in Mr Murat's house, for instance, I have no doubt that his car would have been the one the dogs were repeatedly brought back to ( and quite rightly )
To present the explanation that the dogs alerted as they did, only because their handler 'cued' them to, is entirely unsupportable and lacks reason