Hell i love my dogs but would not trust them at all. I let them lick my hand and my arms and legs if they want but if they go to lick my face then they are put down this is not good because if you let them in that far they can do some serious damage dogs have bad days too. Mine are not trained to take anyone down but a German Sheppard or other breeds are trained and bred for this kind of thing so they definitely have more of propensity to do it as for the post man it could have easily been a child dressed in a scouts uniform