By the time the owner gets the "note", chances are the cat will be killed by the "Humane" Society. Talk with the neighbor, use the "Cat Away", but don't terrorize and traumatize these animals. They don't know any better. This is a definate "communicate with the owner", before that type of drastic action is taken. Drastic meaning having them hauled off to be killed.
Oh, and R.Jordan, perhaps you should be "dropped off in the woods" and I could watch you become disoriented, terrified and drop weight from lack of food and water until you die. Yes, that sounds entertaining. I will send you a box to have yourself dumped and hauled away in (to a remote, undisclosed location to you or your family).