I have to agree with you on that one. It doesn't happen anymore, but in past years when I'd have Muffin outside the fenced yard (always on leash though) walking around the yard then every once in awhile here comes someone else's big dog and in my own yard I have to pick up my doggie to keep her safe. And of course to keep her from attacking the big dog!
Then there was the occasional pest that would come into our yard (we have an acre) and up to her fence and drive her nuts!