[Spinnaker]

I am not condoning any thing that will cause injury to your neighbor's cat, since I like most of them and have even had a cat or two parked in the house at times. But, like anything else, they need to know their place and sometimes need some discipline.
I used to feed my cat outside, so she could eat while I was at work. Other cats would come around and eat her food. I didn't want to injure the other cats, but I wanted them to leave her food alone.
After much thought and problem solving head scratching, I came up with this. I took an old ignition coil I had laying around and wired it to a section of cardboard covered with a grid of aluminum foil and put it in front of her food dish. The spark lead goes to one section of the grid, and the ground went to the other section of the grid. I hooked up a micro switch to the 12 volt power lead in order to cycle the power (to simulate opening and closing the points) and used a battery charger for power.
So on weekend, when I was home, I would keep watch for the free loaders. Once they were on the foil pad, I hit the micro switch and you have never seen a cat jump so high in your life.
Nothing like a little electroshock therapy to change some behavior.