One can call it plausible deniability. There are many examples that have been caught on camera, I see that another commenter posted a link to one of them on th

One can call it plausible deniability. There are many examples that have been caught on camera, I see that another commenter posted a link to one of them on this thread. When you see things like the handler returning to a previously cleared spot and indicating that the dog should check it again; three or four times until the dog alerts, you can assume that the handler has a severe short term memory problem and he just forgot that the dog had previously checked the area and failed to alert. I think it's more indicative of the officer hinting to the dog that "this is where I want you to alert" and their training reinforces the idea that if the dog does what's expected, there will be a treat.