What prevents continual alerts at most sites though, if residual scents or contaminants from toenails/ mops/ pork products / nosebleeds/ nappy related substances /saliva etc are what trigger the response?
Surely the searches on most sites would be pointless were this the case.
That`s the point.
That would seem to sum up exactly Mr Amaral's late calling in of dogs which he had been told were available to him shortly after Madeleine's disappearance when, as in the case of the reconstitution they would have been of maximum value and certainly of more use than the excellent GNR sniffers. (please don't require a cite ... it's all in the files)
Do you think that based on the fiasco in Praia da Luz, Haute de la Garenne, Tia Sharpe, Shannon Matthews etc ... VRD and CSI working dogs are 'pointless'.
I think you are misunderstanding the role of the dogs as just one very valuable tool in the box of tools available to investigators ... or is it your suggestion that if you or a loved one is lying under a collapsed building it would be pointless to send the dogs in to find you because there are too many distractions around?