I have a target against the neighbor's fence, with his knowledge and permission. I always check to see that nobody is in his backyard when I shoot. One day I was shooting and an arrow happened to go through the fence between the boards. I looked over the fence, and it was only a few feet away from the fence. I thought I could get it with my rake, so I went to my garage and came back with my rake. When I leaned over the fence with my rake, it got the neighbor's dog's attention, so he came over and ran off with the arrow. I take care of the neighbor's dog when they are gone, so I felt okay about going into their backyard to get my arrow back from the dog. But the dog had hidden the arrow, and I couldn't find it anywhere.
The next morning, the arrow was on top of my newspaper in my driveway. Fortunately, my neighbor is also a hunter, and had good humor about the situation. But I wouldn't imagine that his good humor would last if he found too many of my arrows in his backyard.
Now I have a piece of old carpet hung on my side of the fence, which hopefully will keep the arrows on my side of the fence. Of course, none of my arrows should ever miss by so much that they should even hit the fence, but shoot enough arrows, and I'm sure it will happen again.