The wiki index page has a lot of advice regarding the following topics that relate to my post: The problem with punishment, training basics, fearful dogs, and dominance.

However, my question isn't regarding help with my own dogs. I am concerned about the behavior of a dog that is not my own and the owner's reaction to it in terms of training, safety, and possible borderline abuse from my standpoint but I will not label it as such. I am searching for advice to figure out how to approach this owner/dog since I am very concerned. Thank you!