BTP has been doing this at my local station for quite some time, usually on a Friday night. It's quite unobtrusive, in that the dog and handler stand quite some distance away from the gateline. The dog just sits there patiently until it smells something interesting, and then walks alongside the 'target'. The look on the little herbert's face when he realises that the nice doggy that's just taken a fancy to him has a 6 ft 10" Copper attached to it is a picture to behold.
