Across the street neighbors have a young chocolate lab. He's starting to become protective of their property (especially when their daughter is outside). I get it, but when he starts challenging me on my property that's a problem. Yesterday when I let Maggie out he was on our lawn and started growling at me. Maggie let out her fearsome growl/bark and charged at him. He went home in a hurry. They have invisible fence because the in-laws used it to control Teddy an aggressive pit/chesapeake retriever cross. Talked to the wife, and she realizes the dog is a problem, but her husband (he's a veterinarian) doesn't want to use it. I explained that there are two possibilities: the dog may get hit by a car and killed or the dog may/will bite someone. I also explained that if the dog bites the Princess, Maggie, or me we will have a significant problem. Joggers, bicyclists, walkers with kids frequent our road. It's a problem easily resolved BEFORE it happens.