I just read this whole thread and have been absolutely shocked at some of the things I have read. I think a lot of it boils down to respect. I was raised to respect the property of others and to do my best to refrain from actions that may be a nuisance to someone. That's why I keep my pets inside. Sure, I may not see it as a big deal at all for a cat to roam onto the property of my neighbor, but frankly, it would be pretty presumptuous and self-serving for me to automatically assume that my neighbor feels the same way. It's MY animal and HIS property, so the least I can do is be responsible for my pets and respect his property. Seems pretty simple to me.
I'm not trying to "show that damn cat." I just want the cat off my property. Is that such a hard concept to grasp?
Put a 12 foot fence around your front yard and build a moat then. As long as we have animals (cats, dogs, squirrels, etc etc) not in captivity, they will roam onto your yard from time to time. The fact that it bothers you that much is disturbing.
I must spread reputation around so I can rep this. He should probably build a dome too to keep out those damn birds.