I take my dog to obedience class and she try's to put me between strange dogs and herself. What's going on?

Hello Mr. Frawley,

In the past I have asked you several Questions on Dog Fights regarding the training of my now 14 month old DDR, female, German shepherd dog. As it turns out, every one of your answers has proven to be correct. Thanks. I have one more for you:

Quite often I take my shepherd to a German shepherd breeder/trainer of working dogs. I take her there now primarily for the opportunity to expose her to other dogs, people, horses, and chickens in a controlled situation. I am obedience training her myself and I do work her on the training field with about 6 to 10 other dogs/trainers.

At the training facility my dog shows what would seem to be a rather typical response to the other dogs: She will give the other dogs a glance but pays little attention to them. She does, however, (at least in my opinion) seem to display hesitation and uncertainty when I bring her too close to the other dogs. For example, when the other dogs are sitting nicely in a row, my shepherd will sit or lie next to them (about 3 feet away), but when I walk her down the line of dogs, she wants me to be between the dogs and herself, especially when the dogs are facing us. When we walk behind the row of dogs, she appears much more confident and less intimidated. She also seems a bit uncertain as I try to place her about 3 feet from the other dogs when forming a line of sitting dogs.

When I take her for a walk in the neighborhood, she sometimes/usually becomes aggressive (very loud) when she sees another dog. When I walk her inside a large chain pet store, she is interested in the other dogs/animals she sees, but does not display any aggression. She has never been bitten or even attacked by another dogs. A couple weeks ago a dog on the training field (year old male) did break loose and run at her in an aggressive-play manner, but I did step in between them and for the most part kept them apart.

Why is it that when we are on walks in the neighborhood her behavior appears aggressive when she sees another dog?

Also, what do you do when you have a dog out in public and there is a need to give it a stern correction?

Thanks a lot,
Scott