Hypothetical Situations.....Which of the two is more probable?
A frustrated dog walker who is having marriage problems, just got laid off, and had a fight with their kid comes to your house to let your german shepherd out. Your dog is having to much fun running around and keeps running away so they can't put the collar on him. The handler gets frustrated and begins handling the dog roughly. When they are outside, the handler jerks the dog and yells at it to hurry and potty. The dog doesn't know what to do and tries to get away from the handler, who pops him with the leash. Then there is a bite.
The dog walker loves your dog to death and is in a perfectly happy mood. She lets your dog out of his kennel ,feeds him, then plays with him. Next she takes him outside (as she has every day for the past few months) and out of nowhere he bites her for no reason.
Just bringing up the possibility..