I actually am a little tempted to blow some time implementing something similar this weekend, because an unknown animal keeps leaving droppings in my backyard at random times. I'm less annoyed with that specifically, and more just curious about the phantom pooper in general. And, well, by the time I have the pictures figured out.. I have a Rachio, which means I can turn the sprinklers on through an API call anyway.
If you think it's "natural" and your cats should be free to roam, then you simply should not own cats. Your cat is not just "visiting neighbours". It is destroying other people's yards and killing off local bird populations. Yet you don't care, because it's out of sight and out of mind. All you care about is how you feel for allowing your cat to be free, while shunning all responsibility for how your cat is impacting others.
People who keep "outdoor cats" remind me of an acquaintance I once knew who owned birds with clipped wings, kept in tiny cages for 23-24 hours a day. Her reasoning for not finding it morally reprehensible? "Well these exotic birds cannot survive our Canadian winters, they need to be kept indoors!". So... you're buying exotic birds that do not belong in our climate, mutilating them, imprisoning them... and somehow manage to revamp the logic in your head to make yourself their savior?
I hope one day aliens come to our planet, put us all in 10x10 foot cages after severing our spinal columns so we can't walk, while making sure to let us know it's for our own good and has nothing to do with their own agenda. Or the aliens can come and cohabitate with us, but let their human-eating pets roam outdoors and deny any responsibility for those pets' actions.
Nowadays however we have our own cat. So no more cat shit from the neighbors. That helped wonderfully. Our cat loved to go outdoors, but after a while every other day he catched another bird and was nice enough to bring home his catch. So while it's pretty good for him, he lost his outdoor privileges.
That is.. he still gets to go outdoors, but nowadays I walk him. Yip, that's right, I'm the loony tune that walks his cat. Cats are not the easiest to teach to walk on a leash. But he got used to it and loves it. In fact he asks me to walk him several times a day. Unless it rains then he sleeps.
It's not like walking a dog where you tell the dog where to go, but it's more like you're the dog. He tells you where we go (if we go that is, because he likes to sniff around more as walk)
Anyways, just wanted to say that there are other alternatives for cat lovers then having them terrorize the neighbors and catch birds.
Some animals will become pests no matter what but I've never met someone with such a negative view of outdoor cats it was just a bit surprising.
A cat or two never bothers me. But when my neighbor gets to putting out 5 or 6 food dishes for the strays each Spring, we can easily find a dozen cats in our back yard.
Don't get me wrong, the whole thing was hilarious, and I used to interject little "meows" every now and then just to confuse the cats. It wasn't as funny when I needed to be awake early for an exam or, later in life, while I spent a few months recovering from pretty harsh medical treatment. The solution was keeping a bucket of water next to the window and just get them soaked. That would stop them for a couple weeks at a time.
Yes, there is an advantage on they being around: it keeps the squirrels away from my berry bushes. But I still would prefer they didn't come.