I suppose it depends on your relationship with your neighbors, and if you live out in the country or the suburbs. Personally I think it's incredibly important to train your dog to respect the boundaries of your yard. It's more of a safety issue for the dog, particularly if it's smaller. I have a neighbor down the street who lets her tiny dogs (two of them) roam the neighborhood and it's the worst. The other day I stepped in a pile of dog poop while checking the mail, and vowed to call the county the next time I see them out. People drive up and down our street pretty fast, and they could easily get hit.

I think you should train your dog to poop in the right place. You can monitor the schedule of their pooping everyday so you can put them on the right place to poop.

How old is your dog? I believe it's much easier to change the habit if the dog is still younger. Also, how is your dog going over to the neighbors, and how sure are you that your neighbors don't mind? Have you personally asked them? It's best to have a proper conversation with them because they may be talking about you behind your back or they may not know what your dog is doing and be mad at the poor pupper when caught

I don't encounter that one because My dog poop one side in my yard only. But I saw some dogs doing that in my yard -_- . I think it is there way to tease us haha

This never happened to me because we have big fences here. I think you should monitor your dog and train him to poop in one place, find him the right spot in your yard, he must have a favorite place there.

It is a very bad habit which you have allowed your dog to master and see it as something that is normal for her to do. You should try as much as possible to inculcate in your dog that going over to your neighbor's yard to poop is something that is wrong and she will learn that and stop doing it.