Years ago when I was a courier with FedEx, I was way out in the country to make a delivery. I drove up this long drive on this customers range and was met by a healer that didn't look to happy to see me.
I opened the window and asked the rancher if his dog bites, he said "does he have teeth" point taken and I stayed in the truck.

Moral here is to just keep them on a leash, its easier and less confrontational.